Conclusion: The wall slide is an effective exercise to activate the SA muscle at and above 90° of shoulder elevation. During this exercise, SA activation is not significantly different from SA activation during the push-up plus and scapular plane shoulder elevation, 2 exercises previously validated in the literature. J Orthop Sports Phys Ther 2006;36(12):903-910. doi:10.2519/ jospt.2006.2306