The Relationship Between Lumbar Spine Load and Muscle Activity During Extensor Exercises

The back extensor exercises examined provided a wide range of joint loading and muscle activity levels. Single-leg extension tasks appear to constitute a low-risk exercise for initial extensor strengthening, given the low spine load and mild extensor muscle challenge. When combined with contralateral arm extensions, the challenge and demand of the exercise were increased. The compressive loading and extensor muscle activity levels were highest for the trunk extension exercises.