Discussion
double-leg barbell squats, muscle hypertrophy
The aim of this study was to compare the impact of two different progressive squat programs (bodyweight and barbell-back squat) on body fat, lower limb muscle thickness, and strength in sedentary women over a period of 6 weeks. It examined the specific effects of different postures and angles of bodyweight squats on lower limb muscle strength compared to barbell-back squats. Despite the fact that the number of training repetitions for both groups remained essentially the same, the training mode that increases the level of movement difficulty as the load intensity was found to be just as effective as gradually increasing the barbell weight as the load intensity, which can help increase knee muscle strength and muscle hypertrophy levels for the subject. The study’s main findings revealed that both groups exhibited similar increases in lower limb isokinetic peak torque and muscle thickness, but changes in body fat differed between the two groups.Previous studies have shown that bodyweight squat mode, which focuses on increasing the number of repetitions, can improve the total training volume by increasing the number of repetitions under constant load intensity (bodyweight)With regard to muscle strength, both groups of untrained women experienced comprehensive improvements, including in right knee concentric peak torque of flexor, right knee eccentric peak torque of extensor, and left knee concentric peak torque of extensor. This study further proved that bodyweight squats, using body-weight as the load intensity and focusing on multiple unilateral squats combinations, can achieve a similar increase in knee joint strength as double-leg barbell squats with 60–80% 1RM in short term. Results about the bodyweight squat in this study were also consistent with those of previous studies, which showed that various leg squats can significantly stimulate the quadriceps and hamstringsMeanwhile, previous evidence have shown significant differences in H/Q ratios between dominant and non-dominant legs in young womenIn terms of muscle hypertrophy, early studies generally agree that neural adaptation plays a dominant role during the first 6–7 weeks of training, while muscle hypertrophy changes very little during this periodMuscle cross-sectional areas had a significant relationship with strength-velocity characteristics of the whole muscle and greater force productionFinally, participants in the barbell-back squat group experienced a significant reduction in body fat percentage without a change in body weight, consistent with previous findings that resistance training can lead to rapid decreases in body fat in untrained women