The interaction between strength training and endurance performance has long been studied, with positive effects shown in the research dating back to the ‘80s (1, 2). It is now common place to see endurance athletes including strength sessions in normal training weeks and having specific phases of the macrocycle dedicated to strength blocks. The benefits of strength training can be considered as having direct impacts on performance and indirect outcomes on injury prevention and body composition.
Whether it be running or cycling, there are a number of determinants of endurance performance, including but not limited to – V02 max, running economy, cycling efficiency or power output. While strength training has little impact on V02 max (3, 4), there is significant benefits on endurance economy (5, 6, 7) and power (4, 8).
In runners with similar V02 max scores, running economy is a better predictor of performance (9) and gross mechanical efficiency can vary up to 23.5% at a given power output in cyclists (10). Taken together, these findings suggest that the ability to improve endurance economy will have a beneficial effect on exercise performance. Indeed, in a group of distance runners, twice per week strength sessions during the 20-week off-season phase and once per week during the 20-week competitive season resulted in significant improvements in running economy measured at weeks 20 and 40 (5).
Cycling is often viewed in terms of power-to-weight ratio, and while in reality cycling performance is more complex than a simple equation, the ability to improve either side of the equation will have positive outcomes on overall performance. In a group of elite cyclists undertaking a 10-week combined strength and endurance training block, significant increases in mean power output during a 30-s Wingate sprint and a larger improvement in power output for a given blood lactate level was reported compared to a control group just undertaking endurance training (8).
Injury Prevention: the inclusion of strength training is often seen as a protective action, to reduce the incidence of muscle or joint injuries. Indeed, in a review of the literature, strength training proved highly significant for injury prevention (11). While the underlying mechanisms of how strength training acts as a preventative measure is unclear, this may be related to the strengthening of joint structures and increases in bone mineral content (12).
Body Composition: one of the main concerns within endurance athletes undertaking strength training is the association of becoming “too bulky”. When programmed alongside normal endurance training, in an endurance training vs endurance + strength training model, the addition of strength training did not result in any significant changes in body composition between groups (5, 8). While the same training intervention did see improvements in strength for the endurance + strength groups (5, 8). Taken together, these results would indicate strength training has beneficial effects on performance measures without any detrimental changes in body composition.
Off season: the general program during the off-season should look to develop maximal strength, including two strength sessions per week alongside normal endurance training (5, 8). The strength sessions should focus on heavy leg exercises (5, 8) and reactive strength through plyometrics and counter movement jumps (8).
In season: focus should shift to the maintenance of strength during the competition season, especially reactive strength, programming one strength session per week (5).
Take Home Messages
- Strength training has shown positive effects on endurance performance, through an improvement in running economy or cycling efficiency.
- This can be through direct determinants of performance or indirect outcomes.
- Programme 2 strength sessions per week during the off-season to develop maximal and reactive strength.
- Include 1 strength session per week when in-season to maintain strength qualities.