Thanks again for taking the time to visit my blog, with over 400 visitors last month I am delighted, but more surprised with how many of you have been engaging with what I have to say!! I have some really exciting opportunities hopefully coming up over the next month, so please keep checking back to keep track of these.
This is the second of my blog discussions surrounding the arguments against the Nordic Hamstring Exercise. This one will revolve around the argument that the exercise is non-functional.
“The exercise doesn’t replicate the joint velocities at which injuries occur”
This is true! Therefore the argument is a valid one from a factual point of view, however this doesn’t mean that the exercise is not an effective one for reducing the risk of hamstring injury. Alt et al. (2018) tested participants following completion of their protocol and found that the greatest adaptations to training were actually at the greatest velocity that was tested by the isokinetic dynamometer (150 degrees/sec). This was also reflected in the work of Iga et al. (2012) who demonstrated an improvement in peak eccentric knee flexor torque all the way up to 240 degrees/sec (Table One). Therefore there appears to be a carry over from the exercise into more functional joint velocities, likely due to the physiological changes induced.
Taken From: Iga et al. (2012).
“The exercise is not performed in functional knee joint angles”
With the theoretical consideration that the hamstrings are most at risk of injury closer to terminal knee extension during the gait cycle, there is an argument against the use of the NHE as the exercise is performed at inner ranges. Again, there is evidence to support this theory, with Iga et al. (2012) demonstrating the greatest levels of EMG activity at between 31 and 60 degrees of knee flexion (Table Two). However it is also important to highlight that Iga et al. (2012) also demonstrated significantly increased EMG in the final 30 degrees of range. It is also important to note that although the greatest level of muscular activity may not occur within the final 30 degrees of range there is still a shift in peak torque towards longer muscle lengths due to the eccentric nature of the activity.
Taken From: Iga et al. (2012).
This lack of an ability to reach the final ranges of movement may actually have been addressed within the recent literature of both Presland et al. (2018) and Alt et al. (2018). Presland et al (2018) utilised an individualized approach to NHE progression whereby they provided a weight to those players who were able to complete their NHE down to the final 10-20 degrees of range. There is therefore a potential argument to provide players who cannot reach these end ranges with band assistance as in the paper of Alt et al. (2018) until they are able to complete into the final degrees of range, before then returning them to a bodyweight load. This is in line with the discussion of Presland et al. (2018) who suggests that the benefits of the exercise come from the intensity of the exercise rather than the volume of the training.
Hopefully this again provides you with a couple of research based discussion points in case you are faced with a player/patient who is reluctant to perform the activity.
As always any comments or feedback are appreciated
Alt et al. (2018). Velocity-specific and time-dependent adaptations following a standardized Nordic Hamstring Exercise Training.
Iga et al. (2012). ‘Nordic’ Hamstrings Exercise- Engagement Characteristics and Training Responses.
Presland et al. (2018). The effect of Nordic hamstring exercise training volume on Biceps Femoris long head architectural adaptation.