Kinematic Adaptations Of The Triceps Brachii Following Novel Bilateral Isotonic Training Among Males

Power and acceleration of the triceps brachii are important in various sport contexts. The rate of improvement may differ depending on exercise characteristics. PURPOSE: To measure adaptations in power and acceleration of the triceps brachii among males performing bilateral concentric-only triceps extensions with 3D isotonic resistance. METHODS: We enrolled 37 males to perform a minimum of 5 exercise sessions on separate days involving bilateral triceps extensions. Exercise was performed using a Proteus device, which produces 3D electromagnetic resistance. We tracked the subjects through 10 exercise sessions; 14 subjects were retained through session 10. During each set, we recorded average peak power across all repetitions (mean power), highest power achieved in any repetition (peak power), average peak acceleration across all repetitions (mean acceleration), and highest acceleration achieved in any repetition (peak acceleration). We performed paired samples t-tests to compare values at days 1 and 5 (n = 37) and values at days 5 and 10 (n = 14). Linear regressions estimated the effect of exercise session (1 through 5) on power and acceleration holding age constant. RESULTS: Subjects were 36.5 ± 21.3 years of age, 69.8 ± 3.8 inches in height, and weighed 178.3 ± 32.0 lbs. At intake, mean power was 108.5 ± 74.2 W, peak power was 122.6 ± 80.1 W, mean acceleration was 6.8 ± 5.3 m/s2, and peak acceleration was 9.8 ± 8.4 m/s2. Between sessions 1 and 5, subjects improved 49.5% in mean power (p < 0.001), 48.0% in peak power (p = 0.003), 62.0% in mean acceleration (p < 0.001), and 52.4% in peak acceleration (p < 0.001). Between sessions 5 and 10, subjects improved 25.3% in mean power (p < 0.001) and 29.0% in peak power (p < 0.001). There were no changes in mean acceleration (p = 0.432) or peak acceleration (p = 0.394). Holding age constant, each additional exercise session (1-5) predicted an increase of 12.9 W in mean power (p = 0.003; 95% CI: 4.57, 21.31), 14.3 W peak power (p = 0.002; 95% CI: 5.25, 23.41), 1.0 m/s2 mean acceleration (p = 0.009; 95% CI: 0.26, 1.78), and 1.3 m/s2 peak acceleration (p = 0.217; 95% CI: -0.76, 3.33). CONCLUSION: Males experienced significant improvements in triceps brachii power and acceleration within 5 workouts. Power continued to improve through 10 sessions while improvements in acceleration tapered after 5 sessions.