Strength vs. Endurance: The Science of Hybrid Adaptation

The human body is an incredible negotiator – but balancing muscle hypertrophy with aerobic capacity means us humans have to manage a rather brilliant physiological compromise. Strength training, which stimulates the mTOR signalling effect and promotes muscle protein synthesis and hypertrophy, will eventually create adaptations that we want to potentiate. Endurance exercise ultimately drives the AMPK pathways and stimulate maximum mitochondrial density and oxidative capacity. Historically, this was a problematic relationship – and there was a clear “interference effect” – maximal endurance training would suppress the complete potency of strength adaptation comparatively to the training load – so over time we forgot that these were important processes for athletes and hybrid athletes had to bear the decision of following one or the other.

Current research has shown us that the two systems don’t have to be oppositional and we, as periodization planners can actually manipulate the programming for hybrid athletes to optimize both systems.

Part of the success we have with hybrid athletes, while maintaining a balance concurrently, is ensuring the order of their workouts and rest intervals. Strength sessions should always come before endurance training as the concurrent training of heavy lifts with cardio will only preclude full adaptations of the goal of strength day. For example, cardio utilizes glycogen as fuel for endurance training, so doing cardio prior contributes to considerable loss of strength gains. Some evidence suggests that low-impact endurance (cycling and swimming) would interfere less with strength gains than high-impact (running). In terms of fueling properly for these adaptations, timing carbohydrates around endurance training days and high-volume training days will assist with protein intake 1.6–2.2g/kg body weight, which will enhance muscle protein restoration.

The human body’s adaptive ability relies on overload and recovery. Hybrid athletes are able to perform greater volumes of work.