Fast and ballistic contractions involve greater neuromuscular power production in older adults during resistance exercise

Abstract

Purpose Neuromuscular power is critical for healthy ageing. Conventional older adult resistance training (RT) guidelines typically recommend lifting slowly (2-s; CONV), whereas fast/explosive contractions performed either non-ballistically (FAST-NB) or ballistically (FAST-B, attempting to throw the load) may involve greater acute power production, and could ultimately provide a greater chronic power adaptation stimulus. To compare the neuromechanics (power, force, velocity, and muscle activation) of different types of concentric isoinertial RT contractions in older adults. Methods Twelve active older adult males completed three sessions, each randomly assigned to one type of concentric contraction (CONV or FAST-NB or FAST-B). Each session involved lifting a range of loads (20–80%1RM) using an instrumented isoinertial leg press dynamometer that measured power, force, and velocity. Muscle activation was assessed with surface electromyography (sEMG). Results Peak and mean power were markedly different, according to the concentric contraction explosive intent FAST-B > FAST-NB > CONV, with FAST-B producing substantially more power (+ 49 to 1172%, P ≤ 0.023), force (+ 10 to 136%, P < 0.05) and velocity (+ 55 to 483%, P ≤ 0.025) than CONV and FAST-NB contractions. Knee and hip extensor sEMG were typically higher during FAST-B than CON (all P < 0.02) and FAST-NB (≤ 50%1RM, P ≤ 0.001). Conclusions FAST-B contractions produced markedly greater power, force, velocity and muscle activation across a range of loads than both CONV or FAST-NB and could provide a more potent RT stimulus for the chronic development of older adult power.

The effect of a prior eccentric lowering phase on concentric neuromechanics during multiple joint resistance exercise in older adults

“…17,36 The values generated in the current study were broadly similar to the peak power, force, and velocity values previously reported for young and older adults during isoinertial leg press contractions. 10,17,37 Our finding of greater mean (∆ 6 to 55% across loads), but not peak (∆ −2 to +7% across loads) concentric power immediately after a prior eccentric action, compared with CON-Only, in older adults is consistent with previous reports in young adults of higher mean power performance but no difference in peak power performance. 15 Mean power, as the average rate of performing mechanical work during the whole movement may provide the more meaningful metric of whole movement function, whereas peak power is based on just one instant that in this task occurs relatively late in the movement.…”

“…It involved a comprehensive assessment of neuromechanical variables (i.e., mean, peak, and throughout the contraction measurements of force, velocity, power, and activation), over a wide range of loads typically used for resistance training and, thus, eliminated some limitations of previous studies of younger groups (e.g., less comprehensive measurements and/or a smaller range of loads) 17,36 . The values generated in the current study were broadly similar to the peak power, force, and velocity values previously reported for young and older adults during isoinertial leg press contractions 10,17,37 …”

Effects of Eccentric Phase Velocity on Bench Press Concentric Bar Velocity in the Young and Elderly

“…Indeed, implementing strategies that promote increased muscle power and velocity during the concentric phase can be of great interest. The use of ballistic exercises, for instance, has been shown to yield greater improvements in lower limb velocity (ES: 1.1–6.0) when compared to traditional high-velocity RT at intensities ranging from 20% to 80% 1RM 10 . Thus, our results indicate that increasing the MPV by 10.0% and MP by 11.7% through HV ECC may result in clinically relevant chronic benefits, by acutely enhancing neuromuscular capacity in the elderly, at least in the upper body, with only 30% 1RM.…”

“…For comparisons regarding age groups and intensities, two-way ANOVAs (conditions*age; conditions*intensities) with repeated measures were applied for each variable, and, when appropriate, the differences were verified by Bonferroni post hoc tests. Percentage difference was calculated using the following equation: ([mean 1 -mean 2]/mean 1*100) [10]. Effect sizes (ES) were presented by Cohen's d z , as previously suggested [25].…”

“…Specifically, during power and explosive exercises in which subjects move moderate loads at high velocities, fast concentric actions should be considered [6]. Fast concentrics induce the achievement of greater peak velocity (PV), peak strength, and peak power in the elderly [10]. These benefits are related to neural and peripheral mechanisms, including an increase in muscle force production, fascicle length and angles, increased stiffness of the muscle-tendon unit, and activation of fasttwitch motor units [11].…”