The effect of concurrent strength training on multi-discipline sports performance: A systematic review and meta-analysis.

Concurrent (strength and endurance) training (CT) improves performance within single discipline sports such as swimming, cycling, and running. However, its efficacy in multi-disciplined sport athletes, such as triathletes and duathletes, is largely unknown. This review aimed to examine the effects of CT on time trial performance, maximal oxygen uptake (VO _2max ), lactate threshold (LT), exercise economy (EE), and durability in multisport athletes, compared to endurance training alone. Seven databases were searched to identify studies comparing CT to endurance training alone in triathletes or duathletes on at least one measure of aerobic performance. Randomised and non-randomised controlled study designs in any language were included. The Standard Method for Assessment of Resistance Training in Longitudinal Designs (SMART-LD) checklist was used to evaluate study quality. Ten studies of eight distinct cohorts were included incorporating 114 participants, of which 12.5% were duathletes ( k  = 1), 12.5% long distance triathletes ( k  = 1), and 75% triathletes ( k  = 6). CT had a large effect on strength (g = 1.02, p < 0.001) and moderate non-significant effects on power (g = 0.55, p = 0.059) and durability (g = 0.61, p = 0.065), with no effect on time trial performance, EE, VO _2max or LT measures. Nine studies were evaluated as ‘poor’ quality, with one study evaluated as ‘fair’. This systematic review and meta-analysis revealed that CT has a large effect on strength development, moderate non-significant effects on power and durability, and no impact on VO _2max, EE and LT, in triathletes and duathletes. However, further high-quality research is needed to clarify these findings.