Hip and Knee Extensor Activation During the Hip Thrust and Rear-Foot-Elevated Split Squat in Trained Females

ABSTRACT

McCurdy, K, Walker, J, Kelly, C, and Polinski, M. Hip and knee extensor activation during the hip thrust and rear-foot-elevated split squat in trained females. J Strength Cond Res 35(5): 1201-1207, 2021-The aim of the study was to compare hip and knee extensor muscle activation between the hip thrust (HT) and rear-foot-elevated split squat (RFESS) within different depths and the entire range of motion. Twenty, young adult female subjects (age, 20.9 ± 1.3 years; height, 164.6 ± 7.5 cm; mass 63.2 ± 8.8 kg) with an intermediate level of resistance training experience completed the study. Three repetitions were completed at 80% of the 1-repetition maximum. Gluteus maximus, vastus lateralis, and the medial (semitendinosus and semimembranosus) and lateral (biceps femoris) hamstrings electromyographic data were compared at the top, middle, and bottom one-third of the hip range of motion and for the entire repetition. A repeated-measures analysis of variance was used to test significance set at p ≤ 0.05. All 4 muscles revealed higher (p < 0.001) activation at the top position of the HT compared with the middle and bottom, whereas higher scores (p < 0.001) were found in the bottom position during the RFESS. The HT revealed greater activity (p < 0.001) than the RFESS in all muscles at the top, whereas the RFESS showed higher scores (p < 0.001) than the HT in all muscles in the bottom position. For the entire repetition, the RFESS produce significantly greater vastus lateralis activation (59.4 vs 43.6%). The data indicate that the greatest effect for the HT is demonstrated in the top position and at the bottom for the RFESS. Thus, we recommend to implement both exercises in a training program to maximize gluteus maximus and hamstring activation across the full range of motion. For the greatest vastus lateralis activation, the RFESS is recommended.

Activity of Trunk and Lower Extremity Musculature: Comparison Between Parallel Back Squats and Belt Squats

The back squat is widely used in strength training programs. Alternatively, the belt squat has been gaining popularity since it loads the weight on the hips, as opposed to the shoulders and spine. The purpose of this study was to determine whether using a belt squat would result in less lumbar extensor activation while providing similar excitation of other prime mover and stabilizer musculature. Ten participants (9 males, 1 female; age 29.3 ± 4.9 years; body mass 96.2 ± 17.8 kg) who regularly trained both belt squats and back squats performed three sets of 5 repetitions with 100% bodyweight for each exercise. Peak and integrated muscle activity was calculated and normalized to a maximum voluntary isometric contraction. A one-way ANOVA (p < 0.05) was used to compare conditions. Belt squatting decreased lumbar erector impulse (45.4%) and peak (52.0%) activation as compared to the back squat. Belt squatting did not alter activation of the lower extremities except for a decrease in the gluteus maximus (35.2% impulse and 32.1% peak), gluteus medius (54.1% impulse and 55.2% peak). Furthermore, belt squatting reduced activation of the rectus abdominus (44.3% impulse; 31.1% peak), and external obliques (45.8% impulse; 53.7% peak) as compared to back squatting. Our results suggest belt squatting provides similar muscular demands for the quadriceps, hamstrings, and plantar flexors, but is less demanding of trunk stabilizers, and gluteual muscles. Belt squats may be a suitable alternative to back squats in order to avoid stressing low back or trunk musculature.