Comparison of Kinematics and Electromyographic Activity in the Last Repetition during Different Repetition Maximums in the Bench Press Exercise

Abstract

The barbell bench press is often performed at different repetition maximums (RM). However, little is known about the last repetition of these repetition maximums in terms of movement kinematics and electromyographic activity in the bench press. This study compared kinematics and electromyographic activity during the last repetition of 1-RM, 3-RM, 6-RM, and 10-RM on the barbell bench press. Twelve healthy recreationally bench press-trained males (body mass: 84.3 ± 7.8 kg, age: 23.5 ± 2.6 years, height: 183.8 ± 4.2 cm) performed the bench press with a self-chosen grip width with four different repetition maximums. The participants bench pressed 96.5 ± 14.1, 88.5 ± 13.0, 81.5 ± 12.3, and 72.8 ± 10.5 kg with the 1-RM, 3-RM, 6-RM, and 10-RM. No differences were found between the bench press conditions in kinematic or electromyographic activity, except for the 10-RM, where a higher barbell velocity was observed at peak barbell deacceleration and first minimum barbell velocity (p ≤ 0.05) compared to the 1-RM and 3-RM. Overall, triceps medialis activity increased, whereas biceps brachii activity decreased from the pre-sticking to post-sticking region for all bench conditions (p ≤ 0.05). Since slower barbell velocity was observed in the sticking region for the 1-RM and 3-RM conditions compared to the 10-RM condition, we suggest training with these repetition maximums to learn how to grind through the sticking region due to the principle of specificity when the goal is to enhance maximal strength.

The Effect of Sex and Different Repetition Maximums on Kinematics and Surface Electromyography in the Last Repetition of the Barbell Back Squat

“…From a biomechanical perspective, this was expected, as per-set repetitions and barbell load are inversely related; hence, lower per-set repetition ranges should be influenced by more moments of inertia, resulting in a slower ascent phase. This was in accordance with what was reported in bench press activity: significantly higher peak barbell velocities in the sticking region of 10RM compared to 1RM [ 14 ]. Conveniently, we observed a difference in timing to V max2 , which is the event subsequent to the sticking region.…”

“…However, none of the aforementioned studies have compared biomechanics around the sticking region directly between different RMs in the squat. In bench press, in the last repetition of 1-, 3-, 6-, and 10RM, kinematics and surface electromyography (sEMG) were compared [ 14 ], finding mostly similar sEMG and joint kinematics between the conditions, but higher barbell velocity across two events in 10RM compared to 1RM. The extension of these findings to the squat is currently unknown, as the squat engages larger muscle groups, which is known to impose heightened metabolic demands [ 15 ].…”

Comparison of kinematics and electromyography in the last repetition during different maximum repetition sets in the barbell back squat

“…The objective of the current study was to compare kinematics and EMG amplitude in the lower body in the last repetition when performing the barbell back squat of different RM (1, 3, 6, and 10RM). The main findings were that barbell velocity was not influenced by repetition range, in contrast to a similar analysis in bench press ( Larsen, Haugen & van den Tillaar, 2022 ) that observed a higher velocity at 10RM in the sticking region compared to 1 and 3RM. However, in comparison to 1, 10RM revealed more trunk lean at V max1 and V 0 , accompanied by lower EMG amplitude for the vastus lateralis and soleus in the sticking and post-sticking regions and in the gastrocnemius for all phases of the lift.…”

“…Earlier research supports the assumption that technical variations depend on load, as evidenced by the influence of load on EMG signals ( Mehls et al, 2021 ; Martinez, Coons & Mehls, 2023 ). Repetition range might influence joint and barbell kinematics and EMG amplitude during different phases of the lift due to compensatory strategies, which are indirect measures ( Morton et al, 2019 ; Larsen, Haugen & van den Tillaar, 2022 ) of understanding differences between a given repetition range and 1RM squat strength. When attempting to complete the lift, athletes experience several events in the ascending phase, including the sticking region, as a result of a mechanical disadvantage that the athlete has to grind through to complete the lift ( Suchomel et al, 2018 ).…”

“…Although several mechanisms can lead to concentric neuromuscular failure ( Larsen, Haugen & van den Tillaar, 2022 ), similar EMG and kinematics in the different phases of the last repetition when performing squats of different repetition ranges could indicate similar requirements to grind through the sticking region. This knowledge could aid in constructing training programs tailored to specific goals by selecting a repetition range with similar technical requirements.…”