Purpose: To investigate the effects of a sport-specific maximal 6-wk strength and conditioning program on critical velocity (CV), anaerobic running distance (ARD), and 5-km time-trial performance (TT).
Methods: 16 moderately trained recreational endurance runners were tested for CV, ARD, and TT performances on 3 separate occasions (baseline, midstudy, and poststudy).
Design: Participants were randomly allocated into a strength and conditioning group (S&C; n = 8) and a comparison endurance-training-only group (EO; n = 8). During the first phase of the study (6 wk), the S&C group performed concurrent maximal strength and endurance training, while the EO group performed endurance-only training. After the retest of all variables (midstudy), both groups subsequently, during phase 2, performed another 6 wk of endurance-only training that was followed by poststudy tests.
Results: No significant change for CV was identified in either group. The S&C group demonstrated a significant decrease for ARD values after phases 1 and 2 of the study. TT performances were significantly different in the S&C group after the intervention, with a performance improvement of 3.62%. This performance increase returned close to baseline after the 6-wk endurance-only training.
Conclusion: Combining a 6-wk resistance-training program with endurance training significantly improves 5-km TT performance. Removing strength training results in some loss of those performance improvements.