Comparison of isolated lumbar extension strength in competitive and noncompetitive powerlifters, and recreationally trained men

Low back strength has been shown to significantly impact performance in a plethora of sports. Aside from its effect on sport performance, low back strength is strongly associated with low back pain. A sport that heavily involves the lower-back musculature is powerlifting. This study looked to compare isolated lumbar extension (ILEX) strength in competitive and non-competitive powerlifters, and recreationally trained men. Thirteen competitive powerlifters (CPL group; 31.9 ± 7.6 years; 173.4 ± 5.5 cm; 91.75 ± 18.7 kg), 10 non-competitive powerlifters (NCPL group; 24 ± 3.5 years; 179 ± 4.8 cm; 92.39 ± 15.73 kg), and 36 recreationally trained men (RECT group; 24.9 ± 6.5 years; 178.5 ± 5.2 cm; 81.6 ± 10.0 kg) were tested for ILEX. Isolated lumbar extension strength was measured at every 12° throughout subject's full range of motion (ROM) and expressed as the following: “strength index (SI)” calculated as the area under a torque curve from multiple angle testing, average torque produced across each joint angle (AVG), and maximum torque produced at a single angle (MAX). Deadlift and squat strength were measured using 1 repetition maximum for the competitive and non-competitive powerlifters. The following powerlifting characteristics were recorded for the competitive and non-competitive powerlifters: primary deadlift stance, primary squat bar position, use of belt, use of performance-enhancing drugs, and use of exercises to target the lower back musculature. Significant between group effects were found for subject characteristics (age, stature, body mass, and ROM). However, analysis of covariance with subject characteristics as covariates found no significant between group effects for SI (p = 0.824), AVG (p = 0.757), or MAX (p = 0.572). In conclusion, this study suggests that powerlifting training likely has little impact on conditioning of the lumbar extensors.