Compared Analysis of Muscle Activation during Piston Resistance Training and Free-Weight Training

Nicole Hernandez


Purpose: This study compares the amount of muscle activation in a piston resistance machine to that of free weight resistance training. Methods: Thirty recreational athletes who participated in regular resistance training were recruited to perform five repetitions of squats and toe raises using free weights and a piston resistance machine at 70% of their one-repetition maximum. Muscle activation was recorded by surface electromyography electrodes at the vastus lateralis, vastus medialis, lateral gastrocnemius, and medial gastrocnemius. Results: For the squat exercise, there was no significant difference (p > .05) in the vastus medialis between free weight mean muscle activation (0.55 ± 0.58 mV) and piston resistance muscle activation (0.71 ± 0.75 mV) or the vastus lateralis (p > .05) during the free weight condition (0.49 ± 0.43 mV) and piston resistance condition (0.50 ± 0.44 mV). For the toe raise, there was no significant difference recorded in mean muscle activation (p > .05) for the lateral gastrocnemius between free weights (1.31 ± 1.59 mV) and piston resistance (1.20 ± 0.92 mV), or in the medial gastrocnemius (p > .05) between free weights (1.59 ± 1.40 mV) and piston resistance (1.60 ± 1.53. A high correlation was found in the vastus lateralis (r = 0.925, p < 0.001) and the vastus medialis (r = 0.809, p < 0.001) between resistance conditions during a squat. A low correlation was found in the lateral and medial gastrocnemius between free weight and piston resistance conditions during a toe raise at p > 0.05 with R values of 0.215 and 0.348, respectively. Conclusion: No statistically significant differences were found in muscle activation of any muscle group between either conditions. Muscle activation in free weights is similar to the muscle activation in piston resistance training, especially in the quadriceps group. Further studies are needed to test upper body muscle groups for an overall comparison of muscle activation between Nitroforce and free weights.


resistance, piston, training

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