Balance out your training. Improve core strength, overall balance, and—yes—even your posture by adding our TRX® Stability Ball to any workout. There’s nothing like the instant core challenge a stability ball adds, whether you’re performing basic crunches or going high-octane with speedy woodchops, for sport, rehab, and overall fitness. Plus, use it to improve flexibility and proprioception (that’s fit speak for coordination and strength, like when doing planks off the ball). Hand-crafted with durable, non-slip vinyl that won’t pop from heavy use. Available in 55 or 65 cm.