Peak of neuromuscular activation and angle where it occurs during bench press exercise performed with different repetition number and duration in resistance trained individuals

• Published in: Journal of biomechanics Vol. 98; p. 109465
• Main Authors: Lacerda, L.T., Chagas, M.H., Gurgel, M.S., Diniz, R.C.R., Lanza, M.B., Peixoto, G.H.C., Andrade, A.G.P., Lima, F.V.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 02-01-2020; Elsevier Limited
• Subjects: Activation; Amplitudes; Electrodes; Electromyography; Electromyography peak; Human movement; Hypotheses; Muscles; Range of motion; Repetition; Strength training; Training; Triceps brachii muscle; Velocity; Range of motion; Electromyography peak; Human movement
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2019.109465

The present study compared neuromuscular activation, measured by surface electromyography (EMG) amplitude [measure by EMG peak (EMGPEAK)] and range of motion (ROM) where EMGPEAK occurred between two training protocols, matched by time under tension, but with a different number and duration of repetitions. Sixteen recreationally trained males performed 2 training protocols with 3 sets, 180 s of rest with 60% of one-repetition maximum(1RM) on the bench press performed in a Smith machine. Protocol A consisted of 6 repetitions with a repetition duration of 6 s and protocol B consisted of 12 repetitions with a repetition duration of 3 s. EMG activity of anterior deltoid, pectoralis major and triceps brachii muscles were recorded. The results showed a general higher EMG amplitude (regardless of the muscle) in protocol B (p = 0.010), and pectoral and triceps brachii consistently presented higher neuromuscular activation than anterior deltoid at both protocols (p = 0.007). Additionally, the ROM where EMGPEAK occurred in triceps brachii was in the middle of the concentric action (~50% of ROM), this occurred in the first half of the same action (~24% of ROM) in the other muscles. In conclusion, protocol B demonstrated an increased EMG amplitude over protocol A, although both protocols responded similarly by achieving the highest EMG amplitude at same ROM among the muscles analysed.