Clinical trial NCT02674919: Nordic Hamstring and Repeated-sprint Ability in Football (Soccer) Players
Official title: The Efficacy of a 10-week Intervention, Using the Nordic Hamstring Exercise, on Repeated-sprint Ability in Football (Soccer) Players - a Randomized Controlled Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Repeated-sprint Ability
Keywords: Repeated-sprint ability
Nordic Hamstring exercise
Eccentric hamstring muscle strength
Lead sponsor: Hvidovre University Hospital
Sponsor class: OTHER
Collaborators: name: University of Southern Denmark
name: Aspetar
First posted: 2016-02-05
Enrollment: 35
Sex: MALE
Minimum age (years): 17
Maximum age (years): 35
Standard ages: CHILD
ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: OTHER

Brief summary: 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.


Eligibility criteria: 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.

Primary outcomes:
measure: Total sprint time measured during 4x6 sprints of 10 meters. The sprints are performed every 15s and the sets are separated by 3 minutes of rest.
timeFrame: Measured prior to and after the intervention period (at week 0 & 10)
Secondary outcomes:
measure: Single sprint times (best sprint time, sprint time during last sprint).
timeFrame: Measured prior to and after the intervention period (at week 0 & 10)
measure: Maximal eccentric knee flexor strength measured using Nordbord device
timeFrame: Measured prior to and after the intervention period (at week 0 & 10)
measure: Eccentric knee flexor strength endurance measured during 12 repetitions of the Nordic Hamstring exercise using Nordbord device.
timeFrame: Measured prior to and after the intervention period (at week 0 & 10)
measure: Active range of motion of hamstring muscles measured using inclinometer.
timeFrame: Measured prior to and after the intervention period (at week 0 & 10)
measure: Correlation between eccentric hamstring strength and active hamstring flexibility AND sprint performance.
timeFrame: Measured prior to the intervention (at week 0)
Other outcomes:
Locations:
city: Copenhagen
country: Denmark
facility: Both the intervention and testing included in protocol will be conducted in the facilities of the included football clubs in Copenhagen, Denmark.
Study officials:
affiliation: Hvidovre University Hospital. University of Southern Denmark
name: Lasse Ishøi
role: PRINCIPAL_INVESTIGATOR
affiliation: Hvidovre University Hospital. Aspetar
name: Per Hölmich
role: STUDY_CHAIR
affiliation: University of Southern Denmark
name: Per Aagaard
role: STUDY_CHAIR
affiliation: Hvidovre University Hospital
name: Kristian Thorborg
role: STUDY_CHAIR
affiliation: Hvidovre University Hospital
name: Thomas Bandholm
role: STUDY_CHAIR
affiliation: Hvidovre University Hospital. Aspetar
name: Andreas Serner
role: STUDY_DIRECTOR
References:
citation: Mjolsnes R, Arnason A, Osthagen T, Raastad T, Bahr R. A 10-week randomized trial comparing eccentric vs. concentric hamstring strength training in well-trained soccer players. Scand J Med Sci Sports. 2004 Oct;14(5):311-7. doi: 10.1046/j.1600-0838.2003.367.x.
citation: Ishoi L, Holmich P, Aagaard P, Thorborg K, Bandholm T, Serner A. Effects of the Nordic Hamstring exercise on sprint capacity in male football players: a randomized controlled trial. J Sports Sci. 2018 Jul;36(14):1663-1672. doi: 10.1080/02640414.2017.1409609. Epub 2017 Dec 1.