Effect of Weekly Training Frequency With the Nordic Hamstring Exercise on Muscle-Strain Risk Factors in Football Players: A Randomized Trial
Click name to view affiliation
Search for other papers by Thales M. Medeiros in
Current site
Google Scholar
PubMed
Search for other papers by João B. Ribeiro-Alvares in
Current site
Google Scholar
PubMed
Search for other papers by Carolina G. Fritsch in
Current site
Google Scholar
PubMed
Search for other papers by Gabriel S. Oliveira in
Current site
Google Scholar
PubMed
Search for other papers by Lucas Severo-Silveira in
Current site
Google Scholar
PubMed
Search for other papers by Evangelos Pappas in
Current site
Google Scholar
PubMed
Search for other papers by Bruno M. Baroni in
Current site
Google Scholar
PubMed
Purpose: To examine the differences between performing Nordic hamstring exercises once or twice a week on hamstring eccentric strength and other muscle-strain risk factors in high-level football players. Methods: In this randomized trial, 32 football players (18–23 y old) completed an 8-week Nordic hamstring exercise training program in 1 of 2 experimental groups: group 1 (once a week; n = 15) and group 2 (twice a week; n = 17). Knee-flexor/extensor peak torques and biceps femoris long-head muscle architecture were assessed through isokinetic dynamometry and ultrasonography, respectively, before and after the training programs. Analysis of covariance, effect sizes (ESs), and t tests for percentage change were used to assess the effect of the 2 interventions on the outcome measures. Results: Group 2 demonstrated higher hamstring concentric peak torque than group 1 posttraining (155–164 vs 149–158 N·m; P = .043; ES = 0.27), although there was also a statistical trend for higher hamstring eccentric peak torque (212–234 vs 198–221 N·m; P = .098; ES = 0.37), hamstring-to-quadriceps conventional ratio (0.56–0.59 vs 0.54–0.57; P = .089; ES = 0.31), and hamstring-to-quadriceps functional ratio (0.76–0.84 vs 0.71–0.79; P = .076; ES = 0.50). No between-groups differences were found for muscle thickness (P = .864; ES = 0.12), pennation angle (P = .289; ES = 0.18), fascicle length (P = .406; ES = 0.03), and quadriceps concentric peak torque (P = .340; ES = 0.02). Conclusion: Only the Nordic hamstring exercise training program performed twice a week strengthened the hamstrings of high-level football players, while similar changes in muscle architecture occurred with both once- and twice-weekly sessions.
Medeiros, Ribeiro-Alvares, Fritsch, Oliveira, Severo-Silveira, and Baroni are with the Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, Brazil. Pappas is with the University of Sydney, Sydney, NSW, Australia.
© 2023 Human Kinetics