Strength versus Endurance Training

The molecular level research is supporting the macroscopic and microscopic findings on whether strength training and endurance training are mutually exclusive. Certainly there has been much progress since the publication of Dudley's (Sports Med 1987;4:79-85) work. The impression is that there are both central and peripheral factors. At the central level evidence is relatively limited but does seem specific. However, in the neuromuscular setting there are multiple interactions at a variety of levels involving at least three different pathways in muscles and excitatory/inhibitory links all the way to the promotion of mRNA activity. All these steps therefore go against strength and endurance training adaptations being mutually exclusive. If we however just focus on the single-fibre microscopic end result, changes do indeed appear very specific to the demands placed on the body. This fits with the adaptive plasticity of many systems during and after development. This is then affected by additional variables to give the macroscopic changes we have known about for some time. A very complex continuum of load versus response therefore exists with multiple controlling variables. The idea of a ‘single' switch remains elusive.