Does interval cycling after lifting impair size and strength gains?

One of the more challenging aspects of programming for strength and power athlete’s is deciding when and how to implement conditioning work. Despite strength and power sports relying quite little on aerobic energy production, having a reasonable base of fitness can offer numerous indirect benefits. For example, more fit athletes will recover faster between sets and between workouts, enabling for potentially greater training density and/or frequency. There is also some evidence to suggest that higher fitness can improve immune function and reduce your chances of getting sick. Unfortunately, conditioning work tends to “interfere” with strength and power adaptations as well as muscle growth. Therefore, coaches need to strategically implement some form of conditioning work to improve fitness and recovery in their athletes without impacting strength and power gains.

A new study published ahead of print in the Scandinavian Journal of Medicine and Science in Sports investigated whether performing high intensity interval cycling following strength training would impact strength and muscular adaptations. A sample of twenty-two young adult men were randomly assigned to a resistance training group (n=11) or a resistance training plus interval cycling group (n=11). The groups trained twice per week for eight consecutive weeks. Before and after the training program, the researchers measured lower body maximal strength, and rate of force development as well as muscle cross-sectional area of the quadriceps (i.e., thickness), muscle architecture, fiber type composition, capillarization and aerobic capacity.

The results showed that both muscle strength and thickness were significantly improved from pre- to post-training in both groups with no significant difference between groups. Fiber thickness increases were similar among groups but tended to favor the resistance only group. Consistent with previous studies, Type IIa and IIx fibers increased in thickness more than Type 1 fibers. Rate of force development significantly decreased in the resistance plus interval cycling group, as did fascicle angle. Capillary density and aerobic capacity significantly improved only in the resistance plus interval cycling group. Collectively, these results indicate that performing cycle interval training following strength workouts does not appear to effect strength and hypertrophy gains while improving aerobic fitness. However, rate of force development does appear to be negatively affected. This may be a practical way for coaches of strength athletes to program conditioning work with little impact on strength training adaptations.

Reference:

Tsitkanou, S., K. Spengos, A‐N. Stasinaki, N. Zaras, G. Bogdanis, G. Papadimas, and G. Terzis. “Effects of high‐intensity interval cycling performed after resistance training on muscle strength and hypertrophy.”Scandinavian Journal of Medicine & Science in Sports (2016).