Publications by authors named "Andrew J Harrison"

79 Publications

Novel technology in sports biomechanics: some words of caution.

Sports Biomech 2021 Apr 26:1-9. Epub 2021 Apr 26.

Centre for Sport Research, School of Exercise and Nutrition Science, Deakin University, Melbourne, Australia.

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http://dx.doi.org/10.1080/14763141.2020.1869453DOI Listing
April 2021

Onset detection in surface electromyographic signals across isometric explosive and ramped contractions: a comparison of computer-based methods.

Physiol Meas 2021 Apr 12;42(3). Epub 2021 Apr 12.

Biomechanics Research Unit, Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland.

. Accurate identification of surface electromyography (EMG) muscle onset is vital when examining short temporal parameters such as electromechanical delay. The visual method is considered the 'gold standard' in onset detection. Automatic detection methods are commonly employed to increase objectivity and reduce analysis time, but it is unclear if they are sensitive enough to accurately detect EMG onset when relating them to short-duration motor events.. This study aimed to determine: (1) if automatic detection methods could be used interchangeably with visual methods in detecting EMG onsets (2) if the Teager-Kaiser energy operator (TKEO) as a conditioning step would improve the accuracy of popular EMG onset detection methods. The accuracy of three automatic onset detection methods: approximated generalized likelihood ratio (AGLR), TKEO, and threshold-based method were examined against the visual method. EMG signals from fast, explosive, and slow, ramped isometric plantarflexor contractions were evaluated using each technique.. For fast, explosive contractions, the TKEO was the best-performing automatic detection method, with a low bias level (4.7 ± 5.6 ms) and excellent intraclass correlation coefficient (ICC) of 0.993, however with wide limits of agreement (LoA) (-6.2 to +15.7 ms). For slow, ramped contractions, the AGLR with TKEO conditioning was the best-performing automatic detection method with the smallest bias (11.3 ± 32.9 ms) and excellent ICC (0.983) but produced wide LoA (-53.2 to +75.8 ms). For visual detection, the inclusion of TKEO conditioning improved inter-rater and intra-rater reliability across contraction types compared with visual detection without TKEO conditioning.. In conclusion, the examined automatic detection methods are not sensitive enough to be applied when relating EMG onset to a motor event of short duration. To attain the accuracy needed, visual detection is recommended. The inclusion of TKEO as a conditioning step before visual detection of EMG onsets is recommended to improve visual detection reliability.
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http://dx.doi.org/10.1088/1361-6579/abef56DOI Listing
April 2021

Injury Trends in Irish Amateur Rugby: An Epidemiological Comparison of Men and Women.

Sports Health 2021 Mar 3:1941738121997145. Epub 2021 Mar 3.

Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland.

Background: Rugby union is a physically demanding sport that carries an inherent risk of injury. Despite being a popular and widely played team sport, little is known about injuries occurring across the male and female amateur game.

Purpose: To establish and compare injury incidence, nature, and severity in male and female Irish amateur rugby union.

Study Design: Prospective cohort study.

Level Of Evidence: Level 3.

Methods: Data were collected prospectively from 25 male teams (959 players) and 8 female teams (234 players) over 2 full seasons. Both time-loss (24-hour time-loss injury definition) and non-time-loss match injury reports were collected, alongside match exposure data.

Results: Time-loss match injury incidence rates were 49.1/1000 and 35.6/1000 player-hours for male and female players, respectively. Concussion and ankle ligament sprains were the most common diagnoses for male (5.6/1000 and 4.4/1000 player-hours, respectively) and female players (5.5/1000 and 3.9/1000 player-hours, respectively). Anterior cruciate ligament injuries presented the highest injury burden for male and female players with 200.3 and 307.2 days of absence per 1000 player-hours, respectively. In female players, 83% of noncontact injuries occurred in the fourth quarter of match play.

Conclusion: While female players had a lower overall injury incidence rate compared with male players, concussion and ankle ligament injuries were the most common injuries in both cohorts. In female players, a high rate of noncontact injuries in the second half points to the need for strength and conditioning training programs to reduce fatigue-related injuries.

Clinical Relevance: Establishing the incidence and burden of rugby-related injuries is an essential step in minimizing injury risk. This epidemiological information will aid the development of future reduction strategies, including education and coaching strategies and strength and conditioning programs, informed by the most common injuries observed and the mechanism of injury.
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http://dx.doi.org/10.1177/1941738121997145DOI Listing
March 2021

Sprint Start Regulation in Athletics: A Critical Review.

Sports Med 2021 Jan;51(1):21-31

Department of Physical Education and Sports Science, University of Limerick, Limerick, Ireland.

The sprint start in athletics is strictly controlled to ensure the fairness of competition. World athletics (WA)-certified start information systems (SIS) record athletes' response times in competition to ensure that no athletes gain an unfair advantage by responding in < 100 ms after the start signal. This critical review examines the legitimacy of the 100 ms rule, the factors that affect response times and the technologies and rules that support the regulation of the start in competition. The review shows that several SIS use different technologies to deliver the start signal and record response time (RT). The lack of scientific evidence about the definition of the 100 ms false start threshold by the WA is criticized in the literature and the 100 ms rule is challenged. SIS technologies, expertise and sex appear to affect the RT detected in competition. A lack of standardization in event detection has led to validity and reliability problems in RT determination. The onset of the foot response on the blocks is currently used to assess RT in athletics via block-mounted sensors; however, research shows that the onset of arm force reaction is the first detectable biomechanical event in the start. Further research and development should consider whether the onset of arm force can be used to improve the false start detection in competition. Further research is also needed to develop a precise understanding of the event sequence and motor control of the start to improve the SIS technology and rigorously determine the minimum limit of RT in the sprint start.
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http://dx.doi.org/10.1007/s40279-020-01350-4DOI Listing
January 2021

Recommendations for statistical analysis involving null hypothesis significance testing.

Sports Biomech 2020 10 16;19(5):561-568. Epub 2020 Jul 16.

National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University , Loughborough, UK.

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http://dx.doi.org/10.1080/14763141.2020.1782555DOI Listing
October 2020

Effects of task difficulty on centre of pressure excursion and its inter-trial variability in acrobatic gymnastics pyramid performance.

Sports Biomech 2020 Jun 22:1-16. Epub 2020 Jun 22.

Physical Performance & Sports Research Center, Pablo de Olavide University , Seville, Spain.

Despite the importance of balance in Acrobatic Gymnastic Pyramid performance, there is limited biomechanical analysis of balance during this activity. The aims of this study were to analyse the effect of pyramid difficulty on the centre of pressure (COP) excursion and its inter-trial variability, and determine which parameters had strongest relationship with performance. Forty-seven acrobatic gymnasts performed five trials of back and front pyramids and a third more difficult, handstand pyramid on a force platform. Pyramids were held for 7 seconds and surface area, range, mediolateral amplitude and anteroposterior amplitude of the CoP were examined to analyse balance. The pyramid scores were obtained from qualified judges to assess the performance. Results showed higher CoP excursions and inter-trial variability during the execution of the high difficulty pyramid. Higher judges' scores were associated with lower CoP excursions in all the pyramids regardless of the difficulty. Similarly, correlation between inter-trial variability and pyramid performance was observed, although these coefficients were lower than those reported for the relationship between CoP excursion and performance. These results suggested that CoP monitoring could help coaches and gymnasts to assess the pyramid instability more accurately.
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http://dx.doi.org/10.1080/14763141.2020.1770322DOI Listing
June 2020

Injury surveillance and prevention practices across Rugby schools in Ireland.

Phys Ther Sport 2020 May 26;43:134-142. Epub 2020 Feb 26.

Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland; Health Research Institute, University of Limerick, Limerick, Ireland.

Objectives: To ascertain the extent of injury surveillance and prevention practices currently in operation and the availability of qualified personnel across Rugby playing schools in the Republic of Ireland.

Design: Cross-sectional survey design.

Setting: Rugby playing schools across Ireland.

Participants: The Rugby games master, head Rugby coach or teacher/coach with knowledge of all Rugby activities in the school.

Results: Ninety-three Rugby playing schools responded and reported 356 (97% male, 3% female) school Rugby teams. Rugby injuries were formally monitored in 86% of schools. Injury recorders were primarily coaches (61%). Physiotherapy provision was available in 28% of schools, 14% of schools provided access to a medical doctor and 44% of schools provided access to an S&C coach. Structured warm-ups were undertaken in 66% of schools, weekly gym sessions in 49% of schools and 31% of schools did not implement any formal injury prevention measures.

Conclusions: Injury monitoring practices, medical personnel accessibility and the frequency of injury prevention practices varies considerably across Rugby playing schools in Ireland. Future injury surveillance and prevention systems should be suitable for use by non-medical personnel and reflect the structural organisation of the school Rugby game so that data are not solely representative of the elite, well-resourced schools.
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http://dx.doi.org/10.1016/j.ptsp.2020.02.006DOI Listing
May 2020

Limits in reliability of leg-spring and joint stiffness measures during single-leg hopping within a sled-based system.

PLoS One 2019 5;14(12):e0225664. Epub 2019 Dec 5.

Biomechanics Research Unit, Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland.

Research examining the reliability of stiffness measures during hopping has shown strong consistency in leg-spring stiffness (kleg), but high variability in joint stiffness (kjoint) measures. Sled-based systems (SBS) reduce movement degrees-of-freedom and are used to examine stretch-shortening cycle (SSC) function under controlled conditions. The aim of this study was to examine the reliability of kleg and kjoint during single-leg hopping within an SBSKinematic and kinetic data were collected on four occasions (Day_1, Day_2, Day_3 and Day_3Offset). Participants completed two trials of single-leg hopping at different frequencies (1.5, 2.2 and 3.0 Hz) while attached to an inclined-SBS. Stiffness was determined using models of leg-spring (kleg) and torsional (kjoint) stiffness. Statistical analysis identified absolute and relative measures of reliability. Results showed moderate reliability for kleg at 1.5 Hz between inter-day testing bouts, and weak consistency at 2.2 and 3.0 Hz. Examination of intra-day comparisons showed weak agreement for repeated measures of kleg at 1.5 and 2.2 Hz, but moderate agreement at 3.0 Hz. Limits in kleg reliability were accompanied by weak-to-moderate agreement in kjoint measures across inter- and intra-day testing bouts. Results showed limits in the reliability of stiffness measures relative to previous reports on overground hopping. Lack of consistency in kleg and kjoint may be due to the novelty of hopping within the current inclined-SBS. Constraints imposed on the hopping task resulting from SBS design (e.g. additional chair mass, restricting upper body movement) may have also influenced limits in kleg and kjoint reliability. Researchers should consider these findings when employing inclined-SBS of a similar design to examine SSC function.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0225664PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6894759PMC
April 2020

Examining the Reliability of the Landing Error Scoring System With Raters Using the Standardized Instructions and Scoring Sheet.

J Sport Rehabil 2020 May 2;29(4):519-525. Epub 2019 Oct 2.

Context: Dynamic movement-based screens, such as the Landing Error Scoring System (LESS), are becoming more widely used in research and practical settings. Currently, 3 studies have examined the reliability of the LESS. These studies have reported good interrater and intrarater reliability. However, all 3 studies involved raters, who were founders of the LESS. Therefore, it is unclear whether the reliability reported reflects that which would be observed with practitioners without such specialized and intimate knowledge of the screen and only using the standardized set of instructions.

Objective: To investigate the interrater and intrarater reliability of the final score and the individual scoring criteria of the LESS.

Design: Reliability protocol.

Setting: Controlled laboratory.

Participants: Two raters scored 30 male participants (age = 21.8 [3.9] y; height = 1.75 [0.46] m; mass = 75.5 [6.6] kg) involved in a variety of college sports.

Main Outcome Measure: Two raters using only the standardized scoring sheet assessed the interrater reliability of the total score and individual scoring criteria independently of each other. The principal author scored the videos again 6 weeks later for the intrarater reliability component of the study.

Intervention: Participants performed a drop box landing from a 30-cm box was recorded with a video camera from the front and side views.

Results: The intraclass coefficients interrater and intrarater reliability for the total scores were excellent (intraclass coefficients range = .95 and .96; SEM = 1.01 and 1.02). The individual scoring criteria of the LESS had between moderate and perfect agreement using kappa statistics (κ = .41-1.0).

Conclusion: The final score and individual scoring criteria of the LESS have acceptable reliability with raters using the standardized scoring sheet. Practitioners using only the standardized scoring sheet should feel confident that the LESS is a reliable tool.
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http://dx.doi.org/10.1123/jsr.2018-0387DOI Listing
May 2020

Sprint start performance: the potential influence of triceps surae electromechanical delay.

Sports Biomech 2019 Oct 1:1-18. Epub 2019 Oct 1.

Biomechanics Research Unit, Department of Physical Education and Sport Sciences, University of Limerick , Limerick , Ireland.

In the sprint start, a defined sequence of distinct response delays occurs before the athlete produces a movement response. Excitation of lower limb muscles occurs prior to force production against the blocks, culminating in a movement response. The time delay between muscle excitation and movement, electromechanical delay (EMD), is considered to influence sprint start response time (SSRT). This study examined the delay in sprint start performance from EMD of the triceps surae muscle and examined whether certain sprinters gain an advantage in SSRT. Nineteen experienced sprinters performed sprint starts from blocks, with SSRT measured by an International Association of Athletics Federations (IAAF)-approved starting block system. EMD times were detected during a heel-lift experiment. Using revised SSRT limits, based on concerns over the validity of the IAAF 100 ms false start limit, EMD produced a significant moderate correlation with SSRT ( = 0.572, = 0.011). Regression analysis determined that together, EMD and signal processing time (the delay between the auditory signal and muscle excitation) accounted for 37% of the variance in SSRT. Initial results suggest EMD is part of the response time process and that certain athletes may gain a performance advantage due to reduced EMD.
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http://dx.doi.org/10.1080/14763141.2019.1657932DOI Listing
October 2019

An Examination of the Relationship Between the Functional Movement Screen, Landing Error Scoring System, and 3D Kinematic Data During a Drop Jump Task.

J Strength Cond Res 2019 Sep 6. Epub 2019 Sep 6.

Department of Physical Education and Sports Science, Physical Education and Sports Science, University of Limerick, Limerick, Ireland.

Everard, E, Lyons, M, and Harrison, AJ. An examination of the relationship between the functional movement screen, landing error scoring system and 3D kinematic data during a drop jump task. J Strength Cond Res XX(X): 000-000, 2019-Tests such as the Functional Movement Screen (FMS) and Landing Error Scoring System (LESS) have become an established component of preparticipation screening. Despite their practical use, there is a lack of empirical evidence examining their relationship to established assessments of movement, such as 3D kinematics of a drop jump. Fifty-two male collegiate athletes undertook the LESS, FMS, and a drop jump where 3D lower-limb kinematic variables were assessed. Spearman correlations were conducted to examine the relationship between LESS, FMS, and drop-jump 3D kinematic variables. A series of independent t-tests examined differences in hip and knee kinematic variables in acceptable and poor FMS and LESS groups as determined by established cut-off scores. Landing Error Scoring System scores had significant moderate correlations with most kinematic variables (r = 0.35-0.64; p < 0.01). Subjects with poor LESS scores displayed significantly worse lower-limb kinematics compared with their high-scoring counterparts (effect size = 1.99-2.76, large effect). There were significant moderate correlations with maximal hip and knee flexion (r = 0.46 and 0.39 respectively; p < 0.01) and small or nonsignificant correlations between all other kinematic variables and FMS scores. Hip flexion and knee valgus at maximal displacement were the only kinematic variables significantly different between FMS groups (ES = 0.70-0.72, small-to-moderate effect). The results confirm limitations in the ability of the FMS to distinguish between groups for landing biomechanics.
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http://dx.doi.org/10.1519/JSC.0000000000003261DOI Listing
September 2019

The relationship between physical and wellness measures and injury in amateur rugby union players.

Phys Ther Sport 2019 Nov 31;40:59-65. Epub 2019 Aug 31.

Department of Physical Education and Sport Sciences, University of Limerick, Ireland; Health Research Institute, University of Limerick, Ireland.

Objectives: To investigate factors associated with injury in amateur male and female rugby union players.

Design: A prospective cohort study.

Setting: Amateur rugby clubs in Ireland.

Participants: Male (n = 113) and female (n = 24) amateur rugby union players from 5 of the top 58 amateur clubs in Ireland.

Main Outcome Measures: Pre-season testing included physical tests assessing hamstring flexibility, dorsiflexion range of movement, adductor muscle strength and foot position. Wellness questionnaires assessed sleep quality (PSQI), coping skills (ACSI-28) and support levels (PASS-Q). Players were monitored throughout the season for injury.

Results: The time-loss match injury incidence rate was 48.2/1000 player hours for males and 45.2/1000 player hours for females. Two risk profiles emerged involving; 'age + navicular drop + training pitch surface' (53%) and 'age + navicular drop + groin strength' (16%). An inverse relationship between groin strength and groin injury was found for the 'backs' players (-0.307, p < 0.05). Using the PSQI, 61% of players had poor sleep quality, however no relationship between the wellness questionnaires and injury was found.

Conclusion: Two injury risk profiles emerged, associated with subsequent injury occurrence. Using these risk profiles, individualized prevention strategies may be designed regarding deficits in groin muscle strength and identifying foot alignment.
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http://dx.doi.org/10.1016/j.ptsp.2019.08.012DOI Listing
November 2019

NASHA hyaluronic acid for the treatment of shoulder osteoarthritis: a prospective, single-arm clinical trial.

Med Devices (Auckl) 2019 12;12:227-234. Epub 2019 Jun 12.

Research and Development, Bioventus Cooperatief UA, Hoofddorp, Netherlands.

Osteoarthritis of the shoulder or glenohumeral joint is a painful condition that can be debilitating. Intra-articular injection with hyaluronic acid should be considered for patients not responding adequately to physical therapy or anti-inflammatory medication. This was a single-arm, open-label, prospective study of a single intra-articular injection of NASHA (non-animal hyaluronic acid) in patients with symptomatic glenohumeral osteoarthritis. Patients were followed up for 26 weeks post-treatment, during which time rescue medication with acetaminophen was permissible. The study objective was to demonstrate that a single injection of NASHA is well tolerated with an over-6-month 25% reduction in shoulder pain on movement, assessed using a 100-mm visual analog scale. Forty-one patients were enrolled, all of whom received study treatment. The mean decrease in shoulder pain on movement score over the 6-month study period was -20.1 mm (95% CI: -25.2, -15.0 mm), corresponding to a mean reduction of 29.5% (22.0, 37.0%). Statistically significant improvements were also observed in shoulder pain at night and patient global assessment. There was no clear change over time in the percentage of patients using rescue medication and mean weekly doses were below 3500 mg. Seventeen patients (41.5%) experienced adverse events, all of which were mild or moderate. Two adverse events (both shoulder pain) were deemed related to study treatment. This study provides preliminary evidence that a single injection of NASHA may be efficacious over 6 months and well tolerated in patients with symptomatic glenohumeral osteoarthritis. Larger studies are needed for confirmation.
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http://dx.doi.org/10.2147/MDER.S189522DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6573776PMC
June 2019

Corrigendum to "Injury surveillance in schools rugby: A systematic review of injury epidemiology & surveillance practices" [Physical Therapy in Sport 38 (2019) 170-178].

Phys Ther Sport 2019 09 26;39:44. Epub 2019 Jun 26.

Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland; Health Research Institute, University of Limerick, Limerick, Ireland.

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http://dx.doi.org/10.1016/j.ptsp.2019.06.011DOI Listing
September 2019

The effect of running speed on joint coupling coordination and its variability in recreational runners.

Hum Mov Sci 2019 Jun 5;66:449-458. Epub 2019 Jun 5.

Running Injury Clinic, Calgary, Canada; University of Calgary, Calgary, Canada. Electronic address:

The purpose of this study was to examine the effect of speed on coordination and its variability in running gait using vector coding analysis. Lower extremity kinematic data were collected for thirteen recreational runners while running at three different speeds in random order: preferred speed, 15% faster and 15% lower than preferred speed. A dynamical systems approach, using vector coding and circular statistics, were used to quantify coordination and its variability for selected hip-knee and knee-ankle joint couplings. The influence of running speed was calculated from the continuous data sets of the running cycle, allowing for the identification of time percentages where differences existed. Results indicate that increases in running speed produced moderate alterations in the frequency of movement patterns which were not enough to alter classification of coordination. No effects of speed on coordination variability were observed. This study has demonstrated that coordination and coordination variability is generally stable in the range of ±15% around of preferred speed in recreational runners.
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http://dx.doi.org/10.1016/j.humov.2019.05.020DOI Listing
June 2019

Injury surveillance in school Rugby: A systematic review of injury epidemiology & surveillance practices.

Phys Ther Sport 2019 07 25;38:170-178. Epub 2019 May 25.

Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland; Health Research Institute, University of Limerick, Limerick, Ireland.

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http://dx.doi.org/10.1016/j.ptsp.2019.05.005DOI Listing
July 2019

Measures of Strength and Jump Performance Can Predict 30-m Sprint Time in Rugby Union Players.

J Strength Cond Res 2019 Apr 17. Epub 2019 Apr 17.

School of Health and Human Performance, Northern Michigan University, Marquette, Michigan.

Furlong, L-AM, Harrison, AJ, and Jensen, RL. Measures of strength and jump performance can predict 30-m sprint time in Rugby Union players. J Strength Cond Res XX(X): 000-000, 2019-Performance and fitness monitoring in Rugby Union often include jumping, sprinting, and strength tests, but repeatability of and relationships between these measures are unclear. The level of interindividual variability in these relationships and their sprint time predictive capabilities are also unknown. This study examined the reliability of, and relationship between, countermovement (CMJJH), squat (SJJH), and rebound (RBJJH) jump heights, rebound jump contact time (RBJCT), estimated 1 repetition maximum back squat relative to body mass (SQBM), and reactive strength index (RSI) to 30-m sprint time of subelite, semiprofessional Rugby Union players. Measurement reliability was very good, with high average intraclass correlation coefficients (≥0.9) and low coefficient of variation (<10.1%). All variables were significantly (p < 0.01) correlated to each other (r > 0.575), except for SQBM (only related to CMJJH, r = 0.621) and RBJCT (only related to RSI, r = -0.727). SJJH and SQBM were the strongest and most consistent predictors of time to 30 m (R = 0.754 ± 0.081; SEE = 0.166 ± 0.025), but variability in SEE magnitude was observed across the group during bootstrapping. Cross-validation showed a mean difference between actual and predicted 30 m times equivalent to 0.22% of the group average time to 30 m. These results support the importance of multiple aspects of fitness training in Rugby Union players for improving performance in short-duration sprinting activities, but highlight the individual nature of their relative importance. Measures of strength and power can be used to predict short sprint performance by the strength and conditioning professional.
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http://dx.doi.org/10.1519/JSC.0000000000003170DOI Listing
April 2019

The Relationship Between Isometric Strength and Sprint Acceleration in Sprinters.

Int J Sports Physiol Perform 2019 Nov 18:1-8. Epub 2019 Nov 18.

Purpose: To examine the relationships between the isometric midthigh pull (IMTP), isometric squat (ISqT), and sprint acceleration performance in track-and-field sprinters and to determine whether there are differences between men and women.

Methods: Fifteen male and 10 female sprinters performed 3 maximal-effort IMTPs, ISqTs, and 3 × 30-m sprints from blocks.

Results: Among the men, the results showed significant negative correlations between IMTP and ISqT peak force; relative peak force; force at 100, 150, and 200 ms; rate of force development (0-150 and 0-200 ms); and impulse (0-200 ms) and 0- to 5-m time (r = -.517 to -.714; P < .05). IMTP impulse (B = -0.582, P = .023) and ISqT relative peak force (B = -0.606, P = .017) significantly predicted 0- to 5-m time. Among the women, no IMTP or ISqT variables significantly correlated with any sprint times. Men measured significantly higher than women for all IMTP measures except relative peak force. Men were significantly faster than women at all splits. When comparing measures of the ISqT, there were no significant differences between men and women.

Conclusions: Variables measured during the IMTP and ISqT significantly correlated with 0- to 5-m sprint performance in male athletes. Isometric strength can have a sizable influence on 0- to 5-m time, but in some cases, the maximum effect could be very small.
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http://dx.doi.org/10.1123/ijspp.2019-0151DOI Listing
November 2019

Resistance Training Practices of Sprint Coaches.

J Strength Cond Res 2019 Feb 7. Epub 2019 Feb 7.

Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland.

Healy, R, Kenny, IC, and Harrison, AJ. Resistance training practices of sprint coaches. J Strength Cond Res XX(X): 000-000, 2019-This study describes the results of a survey of resistance training practices of sprint coaches. This study investigated why sprint coaches prescribe resistance training to their athletes, what exercises they select, and what factors are involved with their selection. Forty-one of 73 (56%) sprint coaches with mean ± SD coaching experience of 8.4 ± 6.4 years were included in this study. Coaches completed an online questionnaire consisting of 5 sections: (a) informed consent, (b) coach background information, (c) coach education and qualifications, (d) coaches' views on resistance training, and (e) exercise selection and preference. The results showed that coaches prescribe resistance training to their sprint athletes to develop strength and power, which they believe will transfer to sprint performance. Coaches prescribed a wide variety of traditional, ballistic, and plyometric exercises, with the hurdle jump found to be the most widely prescribed exercise (93% of coaches surveyed). Coaches selected exercises for a variety of reasons; however, the 3 most prominent reasons were: (a) performance adaptations; (b) practicality; and (c) the targeting of muscles/muscle groups. Coaches prioritized exercises that specifically developed strength, power, and reactive strength for their sprint athletes. This research can be used to develop educational resources for sprint coaches who wish to use resistance training with their athletes. In addition, sprint coaches can use the data presented to expand their current exercise repertoire and resistance training practices.
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http://dx.doi.org/10.1519/JSC.0000000000002992DOI Listing
February 2019

The effects of added mass on the biomechanics and performance of countermovement jumps.

J Sports Sci 2019 Jul 6;37(14):1591-1599. Epub 2019 Feb 6.

a Biomechanics Research Unit , University of Limerick , Limerick , Ireland.

This study examined the kinetic and temporal differences between countermovement jumps (CMJs) and eccentrically loaded CMJs. A survey of 109 coaches and athlete showed that 87% of respondents regularly used jumps with added mass within training. Sixteen male and thirteen female track and field athletes from sprinting, hurdling and jumping events performed 5 bodyweight CMJs 5 jumps wearing a weighted jacket and 5 eccentrically loaded dumbbell (LDB) jumps trials in a randomised order. Peak force (PF), peak power (PP), flight time (FT), concentric time (CON-T), eccentric time (ECT), total time (TIME) and eccentric/concentric ratio (E/C-Ratio) were obtained from force plate data. Statistically significant differences (p < 0.05) with moderate to large magnitude effect sizes were found between men and women in FT, PP and PF but not in any of the temporal variables. The results indicated that the WJ decreased FT in men (↓9%) and women (↓10%) but LDB jumps had similar FT to CMJ. Overall, the results showed that LDB increased the E/C Ratio (↑50% and ↑42%) and decreased CON-T (↓37% and ↓25%) compared with WJ and CMJ respectively. LDB jumping is not recommended as a training modality as it tends to disrupt the relative timing of the jump action.
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http://dx.doi.org/10.1080/02640414.2019.1577120DOI Listing
July 2019

The design, development, implementation and evaluation of IRISweb; A rugby-specific web-based injury surveillance system.

Phys Ther Sport 2019 Jan 17;35:79-88. Epub 2018 Nov 17.

Department of Physical Education and Sport Sciences, University of Limerick, Ireland; Health Research Institute, University of Limerick, Ireland.

Objectives: To describe the development, implementation and evaluation of a comprehensive injury surveillance system.

Design: The four phases; i) A survey of 58 medical professionals working in amateur rugby. ii) The design of a web-based injury surveillance system (IRISweb). iii) Recruitment of 21 of the top 58 amateur clubs to use IRISweb. iv) An evaluation survey of the 21 participating clubs.

Setting: Irish amateur rugby clubs.

Participants: Medical professionals working in amateur rugby.

Main Outcome Measures: Phase one investigated the injury monitoring practices in operation prior to the IRIS project. Phase four investigated the effectiveness and usefulness of IRISweb.

Results: Twenty-one clubs were recruited, however 2 clubs failed to provide a full season of data (10% dropout rate). Eighty-two percent of the remaining 19 clubs rated IRISweb as 'good' or 'very good'. Facilitators of injury surveillance were; increased player adherence (65%) and notifications to update the system (59%), however, poor player adherence (71%) and medical staff availability (24%) were the main barriers.

Conclusions: The IRIS project is the first prospective long-term injury surveillance system in Irish amateur rugby, effectively tracking injuries to guide future evidence-based injury prevention strategies. This study highlights facilitators and barriers to injury surveillance within amateur sport.
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http://dx.doi.org/10.1016/j.ptsp.2018.11.007DOI Listing
January 2019

Does fundamental movement skill proficiency vary by sex, class group or weight status? Evidence from an Irish primary school setting.

J Sports Sci 2019 May 13;37(9):1055-1063. Epub 2018 Nov 13.

a Department of Sport and Health Sciences , Athlone Institute of Technology , Athlone , Ireland.

This study examined fundamental movement skill (FMS) proficiency among male (N = 216) and female (N = 198) Irish primary school pupils from Year 2 to Year 7 (9.0 ± 1.7 years). Following anthropometric measurements, participants were video-recorded performing 15 FMS and scored using the TGMD-3, Victorian Fundamental Movement skills Manual and the Get skilled: Get active guidelines. Percentage mastery ranged between 1.4% (gallop) and 35.7% (slide). A two-way ANOVA evaluated the effect of sex (male/female) and class group (Year 2/3/4/5/6/7) on individual skills, locomotor subtest, object-control subtest and total TGMD-3 (GMQ) scores. No significant sex ×class interaction effects were found. Large effect sizes were reported for male superiority in object-control subtest (η = 0.26) and GMQ (η = 0.16) scores (both p < 0.001). Older classes had higher object-control subtest scores than younger classes, but scores plateaued after Year 5. Furthermore, overweight participants had significantly lower locomotor subtest (p < 0.001, d = 0.7), object-control subtest (p = 0.03, d = 0.3) and GMQ scores (p < 0.001, d = 0.5) than non-overweight participants. This study highlights very poor levels of FMS mastery among Irish schoolchildren and stresses the need for developmentally appropriate, FMS intervention programmes that are inclusive regardless of age, sex or weight status.
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http://dx.doi.org/10.1080/02640414.2018.1543833DOI Listing
May 2019

Larger Countermovement Increases the Jump Height of Countermovement Jump.

Sports (Basel) 2018 Oct 26;6(4). Epub 2018 Oct 26.

Physical Performance & Sports Research, Universidad Pablo de Olavide, Sevilla 41013, Spain.

Simulation studies show that jump performance can be improved by increasing the depth of countermovement. The purpose of this study was to determine how modifications to the depth of countermovement lead to changes in jump height and the biomechanical parameters related to center of mass displacement and force application. Twenty-nine competitive males participated in this investigation, performing nine countermovement jumps using a self-selected, a deep, and a shallow crouch position. Jump height and relative net vertical impulse were greater when using a deeper crouch position, compared to the self-selected position. Force application variables did not report differences, when the deeper countermovement was compared to the self-selected countermovement; although, the shallower countermovement showed higher values in force application parameters. The deeper countermovement jumps achieved higher velocities of the center of mass than the self-selected jumps, while shallower jumps produced lower velocities than the self-selected jumps. The results of this investigation were consistent with simulation studies, showing that deep countermovements increase net vertical impulse, leading to a higher jump height. In addition, the maximum downward velocity was higher, when the crouch position was deeper. Conversely, force-applied variables did not change when jump performance was increased.
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http://dx.doi.org/10.3390/sports6040131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316300PMC
October 2018

Does the McNeill Alexander model accurately predict maximum walking speed in novice and experienced race walkers?

J Sport Health Sci 2018 Jul 10;7(3):372-377. Epub 2016 May 10.

School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, Loughborough, Leicestershire LE11 3TU, UK.

Background: Mathematical models propose leg length as a limiting factor in determining the maximum walking velocity. This study evaluated the effectiveness of a leg length-based model in predicting maximum walking velocity in an applied race walking situation, by comparing experienced and novice race walkers during conditions where strictly no flight time (FT) was permitted and in simulated competition conditions (i.e., FT ≤ 40 ms).

Methods: Thirty-four participants (18 experienced and 16 novice race walkers) were recruited for this investigation. An Optojump Next system (8 m) was used to determine walking velocity, step frequency, step length, ground contact time, and FT during race walking over a range of velocities. Comparisons were made between novice and experienced participants in predicted maximum velocity and actual velocities achieved with no flight and velocities with FT ≤ 40 ms. The technical effectiveness of the participants was assessed using the ratio of maximum velocity to predicted velocity.

Results: In novices, no significant difference was found between predicted and maximum walking speeds without FT but there was a small 5.8% gain in maximum speed when FT ≤ 40 ms. In experienced race walkers, there was a significant reduction in maximum walking speed compared with predicted maximum (<0.01) and a 11.7% gain in maximum walking speed with FT ≤ 40 ms.

Conclusion: Leg length was a good predictor of maximal walking velocity in novice walkers but not a good predictor of maximum walking speed in well-trained walkers who appear to have optimised their walking technique to make use of non-visible flight periods of less than 40 ms. The gain in velocity above predicted maximum may be a useful index of race walking proficiency.
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http://dx.doi.org/10.1016/j.jshs.2016.04.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6189270PMC
July 2018

Dry-Land Resistance Training Practices of Elite Swimming Strength and Conditioning Coaches.

J Strength Cond Res 2018 Sep;32(9):2592-2600

Biomechanics Research Unit, Department of Physical Education & Sport Sciences, University of Limerick, Limerick, Ireland.

Crowley, E, Harrison, AJ, and Lyons, M. Dry-land resistance training practices of elite swimming strength and conditioning coaches. J Strength Cond Res 32(9): 2592-2600, 2018-No research to date has investigated dry-land resistance (RT) training practices of elite swimming strength and conditioning coaches. This is the first comprehensive study exploring dry-land RT training practices in swimming. The aims of this study were to examine (a) the dry-land RT training practices and exercises used by elite swimming strength and conditioning coaches and (b) the rationale provided by coaches about their practices and prescription of specific dry-land RT training exercises. Twenty-three (n = 21 males, n = 2 females) elite swimming strength and conditioning coaches, from Ireland (n = 7), Great Britain (n = 5), Australia (n = 6), and the United States of America (n = 5) were recruited through their specific national governing bodies. Coaches completed an online questionnaire consisting of 7 sections; subject information, informed consent, coach's biography, coach education, current training commitments, dry-land RT training practices and exercises, and additional information. The results showed that coaches had varying levels of experience, education and worked with different level swimmers. A total of 95 dry-land RT training exercises were used by the coaches across 4 different dry-land RT training practices (warm-up, circuit training, traditional RT training and plyometrics). Traditional RT training (87%) was the most commonly practiced. The pull-up and squat were the most popular dry-land RT training exercises used by elite swimming strength and conditioning coaches. Future research needs to focus on exploring the specificity and the transfer of RT training exercises to swimming performance.
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http://dx.doi.org/10.1519/JSC.0000000000002599DOI Listing
September 2018

Application of the principal component waveform analysis to identify improvements in vertical jump performance.

J Sports Sci 2019 Feb 30;37(4):370-377. Epub 2018 Jul 30.

c Biomechanics Research Unit , University of Limerick. Limerick , Limerick , Ireland.

The purpose of this study was to determine the effects of training on the force-, velocity-, and displacement-time curves using principal component analysis (PCA) to examine the pre to post intervention changes. Thirty-four trained women basketball players were randomly divided into training and control groups. The training intervention consisted of full squats combined with repeated jumps. The effects of the intervention were analysed before and after the training period of 6 weeks by comparing the principal component scores. The magnitude of differences within-/between-group were calculated and expressed as standardised differences. After the intervention period, clear changes in principal components were observed in the training group compared to the control group. These were related to the execution of a vertical jump with a faster and deeper countermovement that was stopped with greater force. This resulted in greater force from the start of the upward movement phase which was maintained for a longer time. This increase in force throughout a greater range of motion increased the take-off velocity and consequently jumping height.
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http://dx.doi.org/10.1080/02640414.2018.1504602DOI Listing
February 2019

Current injury monitoring and player education practices in Irish amateur rugby union.

Phys Ther Sport 2018 Sep 28;33:27-32. Epub 2018 Jun 28.

Department of Physical Education and Sport Sciences, University of Limerick, Ireland; Health Research Institute, University of Limerick, Ireland.

Objectives: To ascertain current injury surveillance and player education practices in Irish amateur rugby union.

Design: Cross-sectional survey.

Setting: Amateur rugby clubs in Ireland.

Participants: Medical professionals and rugby coaches of the top 58 amateur rugby clubs in Ireland.

Main Outcome Measures: The survey investigated the current injury and training load monitoring practices in operation in Irish amateur rugby. It also explored whether player education sessions regarding injury prevention and concussion recognition and management were conducted in these clubs.

Results: Forty-four clubs completed the survey, giving an overall response rate of 76%. Ninety-one percent of the responding clubs monitored injuries. Sixty-four percent of these clubs operated return to play protocols for all injuries, while 36% operated return to play protocols for concussion only. Injury prevention education was conducted by 71% of these clubs and 82% educated players on concussion recognition and management.

Conclusions: Implementing effective injury monitoring strategies in both amateur and professional sport settings may aid in minimizing injury risk. In Ireland, 91% of the responding clubs monitored injuries and 71% educated players on injury prevention. By implementing one centralized injury surveillance system for Irish amateur rugby, injury trends can be effectively monitored and used to guide prevention strategies.
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http://dx.doi.org/10.1016/j.ptsp.2018.06.008DOI Listing
September 2018

Influence of Reactive and Maximum Strength Indicators on Sprint Performance.

J Strength Cond Res 2019 Nov;33(11):3039-3048

Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland.

Healy, R, Smyth, C, Kenny, IC, and Harrison, AJ. Influence of reactive and maximum strength indicators on sprint performance. J Strength Cond Res 33(11): 3039-3048, 2019-The primary aim of this study was to assess the relationship between reactive and maximal strength measures with 40 m sprint performance and mechanical properties. Fourteen male and 14 female sprinters participated in this study. On the first day, subjects performed 40 m sprints with 10-m split times recorded in addition to maximal theoretical velocity, maximal theoretical force and peak horizontal power, which were calculated from force-velocity relationships. On the second day, subjects performed isometric midthigh pulls (IMTPs) with peak force (PF) and relative PF calculated, drop jumps (DJs) and vertical hopping where the reactive strength index (RSI) was calculated as jump height (JH) divided by contact time (CT). Pearson correlations were used to assess the relationships between measures and independent samples t-tests were used to assess the differences between men and women. No significant correlations were found between DJ and hopping RSI and sprint measures. A significant strong positive correlation was found between IMTP PF and peak horizontal power in men only (r = 0.61). The male sprinters performed significantly better in all recorded measures apart from hopping (CT, JH and RSI) and DJ CT where no significant differences were found. The lack of association between reactive and maximal strength measures with sprint performance is potentially because of the test's prolonged CTs relative to sprinting and the inability to assess the technical application of force. Several methods of assessing reactive strength are needed that can better represent the demands of the distinct phases of sprinting e.g., acceleration, maximum velocity.
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http://dx.doi.org/10.1519/JSC.0000000000002635DOI Listing
November 2019

A review of the reliability of biomechanical variables produced during the isometric mid-thigh pull and isometric squat and the reporting of normative data.

Sports Biomech 2020 Feb 21;19(1):1-25. Epub 2018 May 21.

Faculty of Education and Sport Sciences, Biomechanics Research Unit, Department of Physical Education & Sports Sciences, University of Limerick, Limerick, Ireland.

The use of isometric strength testing, particularly the isometric mid-thigh pull (IMTP) has increased dramatically over the last decade. The IMTP and isometric squat (ISqT) provide one aspect of performance monitoring with variables such as peak force and rate of force development being derived from the force-time curve. The reliability of some of these variables is conflicting in the literature, and the reporting of the reliability is not standardised across the research. The majority of research only reports intraclass correlation coefficients with very few studies reporting coefficient of variation and 90% confidence intervals. Additionally, methods used to calculate variables from the force-time curve differ across studies. An aim of muscle strength testing is to provide normative values for specific sports, allowing coaches to distinguish between performance levels or evaluate the effects of training on performance. This narrative review aims to evaluate studies that have researched the reliability and/or reported normative data for both tests. Additionally, the testing protocols and the force-time curve analysis techniques utilised are discussed, concluding with practical applications for coaches on the uses and limitations of these tests. Results demonstrate that peak force is the most reliable measure and can be used to determine maximum strength capabilities.
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http://dx.doi.org/10.1080/14763141.2018.1452968DOI Listing
February 2020

Examining the association of injury with the Functional Movement Screen and Landing Error Scoring System in military recruits undergoing 16 weeks of introductory fitness training.

J Sci Med Sport 2018 Jun 15;21(6):569-573. Epub 2017 Jun 15.

Department of Physical Education and Sports Science, University of Limerick, Ireland.

Objectives: To examine the association of injury with the Functional Movement Screen (FMS) and Landing Error Scoring System (LESS) in military recruits undergoing an intensive 16-week training block.

Design: Prospective cohort study.

Methods: One hundred and thirty-two entry-level male soldiers (18-25years) were tested using the FMS and LESS. The participants underwent an intensive 16-week training program with injury data recorded daily. Chi-squared statistics were used to examine associations between injury risk and (1) poor LESS scores, (2) any score of 1 on the FMS and (3) composite FMS score of ≤14.

Results: A composite FMS score of ≤14 was not a significant predictor of injury. LESS scores of >5 and having a score of 1 on any FMS test were significantly associated with injury. LESS scores had greater relative risk, sensitivity and specificity (2.2 (95% CI=1.48-3.34); 71% and 87% respectively) than scores of 1 on the FMS (relative risk=1.32 (95% CI=1.0-1.7); sensitivity=50% and specificity=76%).

Conclusions: There was no association between composite FMS score and injury but LESS scores and scores of 1 in the FMS test were significantly associated with injury in varying degrees. LESS scores had a much better association with injury than both any scores of 1 on the FMS and a combination of LESS scores and scores of 1 on the FMS. Furthermore, the LESS provides comparable information related to injury risk as other well-established markers associated with injury such as age, muscular strength and previous injury.
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http://dx.doi.org/10.1016/j.jsams.2017.05.013DOI Listing
June 2018