Neuromuscular and morphological adaptations to short-term squat and deadlift training in women

Skeletal muscle growth has historically been deemed a slow process. The primary purpose of this study was to examine the time course of adaptations in muscle thickness and activation, lean mass, strength, and vertical jump performance during four weeks of barbell squat and deadlift training in untrained women. A secondary aim was to determine if these responses differ for subjects performing low volume versus high volume training. Forty-seven untrained women (mean ± SD age = 21 ± 3 years; body mass = 63 ± 11 kg; height = 162 ± 7 cm) participated. Upon enrollment, the subjects were randomly assigned to one of three groups: 1) low volume training, 2) high volume training, and 3) control. Training for this study focused on barbell back squats and deadlifts. Each subject trained twice per week for four weeks. Testing occurred on six separate occasions (familiarization, pre, week 1, 2, 3, and 4). Statistical inferences were based on the results from 20 mixed factorial analyses of variance (ANOVAs) and effect sizes. Although there was no significant group × time interaction, both training groups exhibited meaningful increases in the leg extensor peak torque values. EMG amplitude showed no significant changes over time or among groups. Significant increases in leg lean mass were demonstrated for both training groups. There was also a main effect for gynoid lean mass, with increases at weeks two and three. A main effect for time was also demonstrated for VL muscle thickness, and both training groups showed small-to-moderate increases. Muscle thickness for the RF was not affected. There were no significant changes in vertical jump performance. Although the changes demonstrated could be considered small-to-moderate, these results showed evidence of muscular adaptations in women exposed to four weeks of barbell squat and deadlift training.