The preventative effect of the
Nordic hamstring exercise on hamstring injuries in amateur soccer players: a
randomized controlled trial

der Horst N, Smits DW, Petersen J, Goedhart EA, & Backx FJG. The American Journal of Sports Medicine. Online
ahead of print, March 20, 2015.

Take Home Message: A program focused
on eccentric hamstring strengthening may prevent hamstring injuries.

Hamstring strains are common, especially
in soccer, and can result in significant recovery times. Eccentric hamstring
strengthening may be a modifiable risk factor of hamstring strains but it
remains unknown if eccentric strengthening will prevent hamstring injuries.  Therefore, Van der Horst and colleagues
conducted a randomized controlled trial to evaluate the effectiveness of an
eccentric hamstring strengthening program (Nordic Hamstring Exercise [NHE]) in comparison
to no intervention on hamstring injury incidence rates, severity, and time loss
among a male amateur soccer population. 
A total of 579 male soccer players from 32 teams completed the study.
The authors randomized teams to the NHE or control group for the 13 week
intervention program.  The NHE group completed
25 sessions of NHE exercises at the end of practices during the 13 weeks, and
adjustments to the protocol were made for injury.  The training sessions were supervised by the
coach or medical staff. For one year, the medical staff for each team reported
any hamstring injury that required medical attention or time loss from soccer. Thirty-six
hamstring injuries occurred with an incidence rate of 0.7 per 1000 exposure
hours, with a greater occurrence in matches when compared with practices.  There were no group differences for hamstring
injury incidence during the 13 week intervention; however, the chance of a
hamstring injury was 72% lower in the NHE group during the remainder of the
year.  There were no differences in
injury severity between the NHE and control groups. 
Eccentric hamstring strengthening exercises,
such as NHE, may have a positive effect in preventing hamstring injuries for up
to 39 weeks after the program.  The
authors of this study noted that a few teams withdrew or did not have full
compliance due to the soreness affiliated with the NHE protocol.  It would be interesting to investigate the
effectiveness of an NHE program prior to the soccer season. This would prevent soreness
from impeding sport-specific training and lead to the effects of the training
program to peak as the athletes are starting their competitive season.  The overall hamstring incidence rates seem
relatively low within this current study.  Future research could work on replicating this
study to determine if it has a similar effect in other levels of soccer
athletes (e.g., college, high school) as well as to determine its treatment
benefit among athletes with previous hamstring injuries.  Further objective measures of pre- and
post-season hamstring strength would also add value to the effects of this
training program as well as possibly identifying “at risk” athletes who have
suffered repetitive hamstring strains and prescribing this type of program to
them. Despite the need for more evidence, sports medicine clinicians may want
to consider advocating for off-season and pre-season eccentric hamstring
exercises as a possible strategy to reduce the number of hamstring injuries on
their team(s). After all, these exercises can be easily done on the field at
practice with minimal chance of harm and the potential to improve strength and
reduce the rate of hamstring strains.
Questions for Discussion:  Will you use eccentric hamstring exercises to prevent hamstring injuries with any of your athletes/patients?   Will eccentric hamstring exercises
decrease the risk of injury in other groups of athletes? 

Nicole Cattano
by: Jeffrey Driban

Related Posts:

van der Horst, N., Smits, D., Petersen, J., Goedhart, E., & Backx, F. (2015). The Preventive Effect of the Nordic Hamstring Exercise on Hamstring Injuries in Amateur Soccer Players: A Randomized Controlled Trial The American Journal of Sports Medicine DOI: 10.1177/0363546515574057