David A Opar1, Morgan D Williams2, Ryan G Timmins3, Jack Hickey4, Steven J Duhig5, Anthony J Shield6. 1. School of Exercise Science, Australian Catholic University, Melbourne, Victoria, Australia david.opar@acu.edu.au. 2. Faculty of Health, Sport and Science, University of South Wales, Pontypridd, Wales, UK. 3. School of Exercise Science, Australian Catholic University, Melbourne, Victoria, Australia. 4. MD Health Pilates, Melbourne, Victoria, Australia. 5. School of Exercise and Nutrition Science, Queensland University of Technology, Brisbane, Queensland, Australia. 6. School of Exercise and Nutrition Science, Queensland University of Technology, Brisbane, Queensland, Australia Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.
Abstract
BACKGROUND: Hamstring strain injuries (HSIs) are the most common injury type in Australian football, and the rate of recurrence has been consistently high for a number of years. Long-lasting neuromuscular inhibition has been noted in previously injured athletes, but it is not known if this influences the athlete's adaptive response to training. PURPOSE: To determine if elite Australian footballers with a prior unilateral HSI (previously injured group) display less improvement in eccentric hamstring strength during preseason training compared with athletes without a history of HSIs (control group). STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 99 elite Australian footballers (17 with a history of unilateral HSIs in the previous 12-month period) participated in this study. Eccentric hamstring strength was assessed at the start and end of preseason training using an instrumented Nordic hamstring device. The change in eccentric strength across the preseason was determined in absolute terms and normalized to the start of preseason strength. The start of preseason strength was used as a covariate to control for differences in starting strength. RESULTS: The left and right limbs in the control group showed no difference in absolute or relative change (left limb: 60.7 ± 72.9 N and 1.28 ± 0.34 N, respectively; right limb: 48.6 ± 83.8 N and 1.24 ± 0.43 N, respectively). Similarly, the injured and uninjured limbs in the previously injured group showed no difference in either absolute or relative change (injured limb: 13.1 ± 57.7 N and 1.07 ± 0.18 N, respectively; uninjured limb: 14.7 ± 54.0 N and 1.07 ± 0.22 N, respectively). The previously injured group displayed significantly less increase in eccentric hamstring strength across the preseason (absolute change, 13.9 ± 55.0 N; relative change, 1.07 ± 0.20 N) compared with the control group (absolute change, 54.6 ± 78.5 N; relative change, 1.26 ± 0.39 N) for both absolute and relative measures (P < .001), even after controlling for differences in the start of preseason eccentric hamstring strength, which had a significant effect on strength improvement. CONCLUSION: Elite Australian footballers with a unilateral history of HSIs displayed less improvement in eccentric hamstring strength across preseason training. The smaller improvements were not restricted to the previously injured limb as the contralateral limb also displayed similarly small improvements in eccentric strength. Whether this is the cause of or the result of an injury remains to be seen, but it has the potential to contribute to the risk of hamstring strain reinjuries.
BACKGROUND: Hamstring strain injuries (HSIs) are the most common injury type in Australian football, and the rate of recurrence has been consistently high for a number of years. Long-lasting neuromuscular inhibition has been noted in previously injured athletes, but it is not known if this influences the athlete's adaptive response to training. PURPOSE: To determine if elite Australian footballers with a prior unilateral HSI (previously injured group) display less improvement in eccentric hamstring strength during preseason training compared with athletes without a history of HSIs (control group). STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 99 elite Australian footballers (17 with a history of unilateral HSIs in the previous 12-month period) participated in this study. Eccentric hamstring strength was assessed at the start and end of preseason training using an instrumented Nordic hamstring device. The change in eccentric strength across the preseason was determined in absolute terms and normalized to the start of preseason strength. The start of preseason strength was used as a covariate to control for differences in starting strength. RESULTS: The left and right limbs in the control group showed no difference in absolute or relative change (left limb: 60.7 ± 72.9 N and 1.28 ± 0.34 N, respectively; right limb: 48.6 ± 83.8 N and 1.24 ± 0.43 N, respectively). Similarly, the injured and uninjured limbs in the previously injured group showed no difference in either absolute or relative change (injured limb: 13.1 ± 57.7 N and 1.07 ± 0.18 N, respectively; uninjured limb: 14.7 ± 54.0 N and 1.07 ± 0.22 N, respectively). The previously injured group displayed significantly less increase in eccentric hamstring strength across the preseason (absolute change, 13.9 ± 55.0 N; relative change, 1.07 ± 0.20 N) compared with the control group (absolute change, 54.6 ± 78.5 N; relative change, 1.26 ± 0.39 N) for both absolute and relative measures (P < .001), even after controlling for differences in the start of preseason eccentric hamstring strength, which had a significant effect on strength improvement. CONCLUSION: Elite Australian footballers with a unilateral history of HSIs displayed less improvement in eccentric hamstring strength across preseason training. The smaller improvements were not restricted to the previously injured limb as the contralateral limb also displayed similarly small improvements in eccentric strength. Whether this is the cause of or the result of an injury remains to be seen, but it has the potential to contribute to the risk of hamstring strain reinjuries.
Authors: Joel D Presland; Ryan G Timmins; Nirav Maniar; Paul J Tofari; Dawson J Kidgell; Anthony J Shield; Jessica Dickson; David A Opar Journal: Sports Med Date: 2021-07-26 Impact factor: 11.136
Authors: Jordi Vicens-Bordas; Ernest Esteve; Azahara Fort-Vanmeerhaeghe; Mikkel Bek Clausen; Thomas Bandholm; David Opar; Anthony Shield; Kristian Thorborg Journal: Int J Sports Phys Ther Date: 2020-04
Authors: João Gustavo Claudino; Carlos Alberto Cardoso Filho; Natália Franco Netto Bittencourt; Luiz Gilherme Gonçalves; Crislaine Rangel Couto; Roberto Chiari Quintão; Guilherme Fialho Reis; Otaviano de Oliveira Júnior; Alberto Carlos Amadio; Daniel Boullosa; Júlio Cerca Serrão Journal: Sports Med Open Date: 2021-01-28
Authors: Jason Brumitt; Victor Wilson; Natalie Ellis; Jordan Petersen; Christopher John Zita; Jordon Reyes Journal: Int J Sports Phys Ther Date: 2018-06
Authors: Alberto Mendez-Villanueva; Francisco Javier Nuñez; Jose Luis Lazaro-Ramirez; Pablo Rodriguez-Sanchez; Marc Guitart; Gil Rodas; Imanol Martin-Garetxana; Josean Lekue; Valter Di Salvo; Luis Suarez-Arrones Journal: Biology (Basel) Date: 2022-01-03