Nordic Hamstring and Repeated-sprint Ability in Football (Soccer) Players

The Efficacy of a 10-week Intervention, Using the Nordic Hamstring Exercise, on Repeated-sprint Ability in Football (Soccer) Players - a Randomized Controlled Trial

The purpose of the study is to investigate the efficacy of a 10-week intervention, using the Nordic Hamstring exercise, on repeated-sprint ability in male sub-elite football players. The primary outcome measure is total sprint time during 4x6 sprint of 10 meters measured using dual-beam photoelectric cells. Additionally, eccentric knee flexor strength is measured using the Nordbord hamstring strength measure. The hypothesis is that strength training of the knee flexor muscles elicited by the Nordic Hamstring exercise will result in enhanced repetitive sprint-ability expressed as a decrease in total sprint time. Furthermore, baseline data is used to assess to correlation between eccentric hamstring strength and active hamstring flexibility AND sprint performance.

Inclusion Criteria:

• Sub-elite Danish football player
• Age 17-35.
• Able to participate fully in competitive football activities at the time of testing

Exclusion Criteria:

• Hamstring pain resulting in loss of training and matches 2 months prior to study initiation.
• Specific systematic strength training of the hamstring muscles (>1/week) in the preceding 2 months before study initiation.
• Specific systematic sprint training (>1/week) in the preceding 2 months before study initiation.
• Longstanding injury (>6 weeks) in the lower extremities in the preceding 6 months to study initiation.