EMG Activity Of Leg Musculature During The Back Squat With Weightlifting And Running Shoes: 3007 Board #293 May 30, 2

Weightlifting shoes (WL) are almost universally used by weightlifters, yet are not nearly as common in weightrooms, where running/athletic shoes (RS) are more common. While some studies have examined kinematic differences between shoe types in the back squat, no studies have examined this issue with EMG.

Purpose : To compare lower body EMG activity during the back squat between WL and RS in a repeated-measures design.

Methods : Subjects were athletic and moderately resistance-trained young females (n=8, BdM=60.3±8.7kg, age 18-21) and males (n=4, BdM=75.3±11.5kg, age 18-21) with 1-RM back squat between 1-1.5 times body weight (1-RM . Subjects performed five repetitions of back squats at 60%, 70%, and 80% of 1-RM with both RS and WL in random order. EMG activity of the vastus medialis (VMO), vastus lateralis (VL), and biceps femoris (BF) were measured for repetitions 2-4, averaged for further analysis of activity during each load in each shoe condition, and expressed as a percentage of MVC. Synchronized video collected within the EMG software allowed for separation of eccentric and concentric phases. A shoe-type by load by muscle repeated measures ANOVA (2x3x3) was used to evaluate the effects of shoe-type and load on muscle activity. Alpha was set at 0.05.

Results : A main effect for shoe type (p=0.014, partial η2=0.437), load (p=0.006. partial η2=0.37, 60% 1-RM: 115.8±70.0% vs. 70% 1-RM: 114.4±69.6% vs. 80% 1-RM: 123.9±73.1%), and muscle (p=0.009, partial η2=0.425, VMO: 143.6±61.6% vs. VL: 133.5±77.6% vs. BF: 77.0±52.2%) were shown. A statistically significant interaction between shoe type and load was also found (p=0.044, partial η2=0.289, WL 60% 1-RM: 114.5±73.0% vs. WL 70% 1-RM: 101.1±57.4% vs. WL 80% 1-RM: 121.4±72.7% vs. RS 60% 1-RM: 117.1±67.8% vs. RS 70% 1-RM: 127.8±78.5% vs. RS 80%: 126.3±74.5%). No other interactions were found.