Effectiveness and utility are key concepts in training. An exercise can be effective if it improves a metric of interest; for example, back squats are an effective way of improving leg strength. An exercise holds utility if its utilization is beneficial within the constraints of a training program. More often than not, effective exercises provide utility. Sometimes, however, the two aren’t the same.
Where effectiveneness falls short
Drop jumps and hamstring exercises are great examples of where effectiveness and utility can clash. Drop jumps are very effective at enhancing the reactive strength of an athlete, but they can increase the risk of injury if the athlete is poorly conditioned, too heavy, or the box height is too high. The same is true when it comes to hamstring injuries, and the exercise type du jour, eccentric loading. Whilst eccentric hamstring exercises such as the Nordic Hamstring Exercise (NHE) are effective at reducing the risk of hamstring injury – by both increasing the strength of the muscle, as well as promoting architectural changes in the guise of increased fascicle length – they come with two major downsides; high levels of post-exercise muscle soreness, and an increased chance of muscle damage.
As such, whilst the evidence supporting the efficacy of the NHE on hamstring injury reduction is strong, the rates of hamstring injury in sports such as professional soccer have not really decreased. This lack of a reduction in hamstring injuries is primarily down to a lack of adherence to eccentric training protocols, with many coaches and athletes citing the increased soreness following this type of training as one of the main drivers for their lack of uptake. As such, whilst we have a highly effective exercise for reducing the risk of hamstring injuries, that same exercise has less real-world utility – and in fact is ineffective at reducing hamstring injuries – due to poor adherence.
This isn’t a unique problem to the NHE or other eccentric strength exercises. In the public health sphere, there is a huge emphasis on interventions that can be made in order to reduce rates of obesity. By far and away the most effective way at getting obese individuals to lose body fat is through the restriction of calories; in studies where calorie intake is lowered to <1500 calories per day, essentially all obese subjects lose weight. This is fine if the subjects are watched over 24-hours per day (just as in a hospital), but the problem is that it is very hard to get subjects to sustain a low calorie diet in the real world. You might have experienced this yourself (I certainly have), you go on a diet which requires you to reduce your caloric intake, and as a result you feel hungry, tired, miserable – and more likely to binge eat. The fact of the matter is that, for most people most of the time, reducing calories to a level that promotes weight loss is hard work, and, as a result, unsustainable. Once again, whilst we have an intervention that can be effective, adherence to the intervention is low, meaning that the intervention itself ends up being ineffective.
Lining up effectiveness and utility
So what’s the alternative? Recently, I listened to a podcast with Dr Anthony Shield from the Queensland University of Technology. Dr Shield helped drive a lot of the recent research into eccentric loading for hamstring injury reduction. However, in the podcast, he freely admitted that the uptake of exercises such as the NHE was problematic. Despite being a long-term proponent of the NHE (and being part of the development of the NordBord piece of exercise equipment), Dr Shield appears to be a pragmatist; whilst acknowledging that eccentric loading appears to be the superior method for reducing the risk of injury, other, less effective methods may actually hold greater utility, provided they can enhance adherence .
In the case of hamstring injury prevention, this could well be isometric contractions. Whilst they likely don’t subject the muscle to as much force, nor promote the same architectural adaptations as eccentric loading exercises, the lower levels of soreness experienced afterwards, along with the lower perceived risk of injury associated with the exercise, means that their uptake and adherence may be greater – and, as a result, rates of hamstring injury may decline. As such, an exercise that is less effective, may hold greater utility, due to increased adherence. Alongside this, because soreness levels will be lower following isometric loading, it requires less recovery time, and so can be programmed more frequently within the programme, again increasing its utility.
Pragmatism provides value
Such a pragmatic approach illustrates the options that are available to us; we don’t always have to program the “best” exercise, but the one that provides the best balance of adaptation and adherence . That doesn’t mean that we shouldn’t programme NHE, or other eccentric exercises, but that context becomes ever increasingly important. It might be more appropriate to programme NHE/eccentrics in the off-season, where soreness has less of a negative impact on performance, and then perhaps switch to isometrics in-season. It might be that a full pre-season of NHE/eccentrics protects against soreness from in-season eccentric loading via the repeated bout effect. In might be that only very low volumes of eccentric loading exercises are required to maintain the improvements seen from pre-season eccentric loading (again, Dr Shield mentioned that it appears that only two weekly sets of 4 reps of the NHE maintains the adaptations seen from pre-season eccentric loading) – in this context, we realise the positives from prior planning, with the correct placement of exercises throughout the training year reducing the aspects that negatively affect adherence. Similarly, as Vern and Martin discussed on yesterday’s GAINcast, efficiency gains from training strength on the pitch could make such exercises more helpful than potentially more effective exercises in the weight room.
In summary, whilst an exercise might be very effective at eliciting its target adaptation, it may not be all the useful if, for whatever reason, adherence to that exercise is low. In this situation, a pragmatic approach is required; it might be better to select a less effective exercise that gets done more often, then the best exercise which is never completed.