ABSTRACT
For optimal sports performance, many athletes will require a range of physical qualities including strength, power, and aerobic capacity. Subsequently, training is likely to contain periods when concurrent development of fitness components is required and can typically be classified into two simple training paradigms, endurance and strength training. In order to optimize training, the interaction of these fitness components should be considered as endurance training may interfere with strength-training sessions via conflicting molecular signaling which may blunt optimal muscular development. At present, there are a range of conflicting recommendations in the literature, due to the challenges of comparing different training studies and the variables which impact upon the magnitude of adaptation, including volume, intensity (load), rest, sequencing, and concurrent training goals. Most importantly, the overall training stress should be considered to reduce cumulative fatigue and minimize the potential negative effect on strength adaptations via dampened hypertrophic responses. Inter-session rest should be maximized wherever possible to reduce the interaction between competing molecular signaling pathways and provide opportunity to refuel as excesive bouts of training when fuel-depleted may restrict subsequent training intensities and blunt any potential adapatations. When training sessions must be completed in close proximity, sequencing should consider the desired training adaptations. If strength adaptations are a priority, training sessions should be sequenced strength, then endurance to maximize the strength stimulus. Overall, optimal planning during concurrent training is a complex interaction between a range of variables where strength and conditioning professionals should be conscious of a series of factors and select a training regime that minimizes the interference effect within the constraints of their own training logistics.
