Comparison Of Shoe Vs No Shoe On Sagittal Plane Deadlift Biomechanics

Abstract

Deadlifts are often an integral part of training programs to build posterior chain strength and power, but current research has not examined the performance outcomes when performed with and without shoes from a biomechanical perspective. PURPOSE: To examine the differences in lower extremity sagittal plane joint kinetics and peak vertical ground reaction force (vGRF) of a conventional barbell deadlift with and without shoes. METHODS: Ten subjects (age: 27.9 + 3.8 years) who deadlift twice a week for the past 6 months, were free from injury, and had no history of lower extremity surgery were recruited. Subjects first performed a one repetition max (1RM) test in self-selected footwear according to NSCA guidelines. At least 72 hours later subjects returned for a 3-dimensional analysis of their deadlift at 70% of their 1RM. Subjects performed 1 set of 5 continuous reps of a conventional deadlift in both shoe and barefoot conditions in a randomized order. A 5-minute rest was given between each condition. Visual3D was used to process raw marker and force data, calculate peak sagittal joint moments of the ankle, knee, and hip and to find peak vertical ground reaction force during the concentric phase. A one-way repeated measures MANOVA was performed to statistically test differences between shoe and no shoe conditions in the dependent variables. RESULTS: Average 1RM for males and females was 437.5 + 83.4 lbs. and 224.2 + 37.6 lbs., respectively. No significant differences were found in internal hip extension moments (p=0.444, S=2.99 Nm/kg, B=3.05 Nm/kg), knee extension moments (p=0.151, S=0.92 Nm/kg, B=0.81 Nm/kg), ankle plantar flexion moments (p=0.113, S=1.07 Nm/kg, B=1.01 Nm/kg), and peak vGRF (p=0.295, S=1044.9 N, B=1035.2 N) between shoe and barefoot conditions. CONCLUSION: Anecdotal claims suggest performing a deadlift barefoot enhances stability and increases connection to the ground which would lead to improvement in deadlift performance. The lack of difference seen in sagittal plane kinetics and peak vGRF suggest that deadlift performance is unaffected by footwear choice. Future research should investigate if similar results would be attained when subjects’ deadlift performance is tested at various percentages of the 1RM.