Comparison of High Versus Low Eccentric-Based Resistance Training Frequencies on Short-Term Muscle Function Adaptations.

Crane, JS, Thompson, BJ, Harrell, DC, Bressel, E, and Heath, EM. Comparison of high versus low eccentric-based resistance training frequencies on short-term muscle function adaptations. J Strength Cond Res 36(2): 332-339, 2022-Eccentric resistance training is beneficial for improving a number of performance and health metrics. However, the recommendations on eccentric training frequency have not been established. This study investigates the effects of volume-matched resistance training frequency comparing 1 vs. 3 training days per week of isokinetic multiple-joint eccentric training on strength and lower-body function adaptations during a 4-week training period. Thirty subjects were assigned to either 3 days per week (high-frequency [HF]) or 1 day per week (low-frequency [LF]) training conditions for 4 weeks. An eccentric dynamometer was used for the training and testing. Eccentric strength and vertical jump (VJ) measures were taken at Pre, Mid (2 weeks), and Post (4 weeks) intervention. Soreness (visual analog scale [VAS]) and rate of perceived exertion (RPE) were taken throughout the training period. There was no group × trial interaction for eccentric strength (p = 0.06) or VJ (p = 0.87). For eccentric strength, all trials were significantly different (p < 0.001) from each other. For VJ, there was a main effect for trial such that VJ increased from Pre to Post (p < 0.001) and Mid to Post (p < 0.01). High frequency reported lower RPE (p < 0.01) and soreness (p = 0.04) compared with LF. Both HF and LF protocols elicited large (36.8 and 27.4% strength increases, respectively) and rapid neuromuscular adaptations for improved strength. Eccentric-based workload may be dispersed across a given period to allow for reduced soreness and perceived exertion levels without compromising neuromuscular adaptations. Some eccentric training transfer to functional (VJ) task may also be observed, independent of training frequency.