We have posted numerous times over the last few years on velocity-based resistance training as this area of research continues to grow. Bar velocity trackers such as accelerometers and linear position transducers have provided coaches with a simple and (somewhat) affordable means of quantifying barbell work in the gym. This has implications for assessing daily readiness with a quick velocity test with a standardized load that when above or below baseline can possibly reflect performance potential being better or worse, respectively. Barbell velocity can also be useful for prescribing daily loads by predicting your daily 1RM, which is known to fluctuate on a daily basis. An additional way that some coaches use barbell velocity is for prescribing set and rep ranges within zones. For example, a coach can prescribe a load that can be moved maximally at 0.8 m/s and the set will continue until a certain percentage loss in bar speed is achieved. This enables coaches to control exercise quality, and focus in on speed-strength or strength-speed.
A new study published ahead of print in the Scandinavian Journal of Medicine and Science in Sports compared the effects of training with a 20% velocity loss cut-off versus a 40% velocity cut-off per set on muscular and performance adaptations. Twenty-two males were divided into a -20% group and a -40% group. Both groups were put through an 8-week training period that emphasized the squat. The groups used the same relative loads, however the -20% group were told to stop each set once they achieved a 20% reduction in mean velocity whereas the -40% group did not stop each set until a 40% reduction in velocity was achieved. Before and after the training intervention, all subjects had their muscles biopsied for determination of fiber type characteristic and muscle cross-sectional area. In addition, 1RM squat, countermovement jump and 20 m running speed were also evaluated.
The results showed that strength gains in 1RM squat did not differ between groups, however the -20% group saw a significantly greater increase in countermovement jump height compared to the -40% group (9.5% vs. 3.5%, respectively). The -40% groups saw a significantly greater increase in vastus lateralis and intermedius hypertrophy compared to the -20% group. A decrease in Type IIX muscle fiber percentage was observed only in the -40% group. Therefore, it appears that prescribing sets based on velocity loss may be a useful way to target specific adaptations. For example, greater velocity loss may be useful when hypertrophy is the goal while smaller velocity loss may be useful for improving power and explosiveness.
Reference:
Pareja-Blanco, F. et al. (2016) Effects of velocity loss during resistance training on athletic performance, strength gains and muscle adaptations. Scandinavian Journal of Medicine and Science in Sports, In Press.
