Abstract

A kettlebell is a steel ball with a horseshoe shaped handle. They have been used as an exercise tool in Russia since the 1700’s and have seen somewhat of resurgence in the United States and other western countries in the last ten years [1]. This resurgence has been, at least in part, due to the popularity of group fitness classes and high intensity interval training (HIIT) methodology. Training with kettlebells is, in some ways, preferable to conventional resistance training. Kettlebell exercises are simpler and faster to learn than many resistance training techniques and can be instantly switched between bi-lateral and uni-lateral exercises. Purported benefits of kettlebell training include the following: improved core stability, cardiovascular benefits, body composition improvements, and increases in muscular strength, endurance, and power. However, despite its long and storied history, there is little clinical evidence to support the claimed benefits kettlebell training provides. Many gaps in the literature exist and what evidence we do have is less than ten years old. What follows is a brief assessment of what we know about kettlebell training and a summary of the questions that remain unanswered. The most common kettlebell exercise is the swing, which is also one of the oldest competitive sporting events in Russian history [1]. The current commonly accepted swing technique was described by Tsoutline [1]. In brief, a proper swing involves holding the kettlebell by its handle in both hands with the arms fully extended. Initially the subject keeps the back straight; hinging the hips the shoulders come forward, driving the hips back allowing the bell to rest between the legs. This is the initial position. The swing begins as the subject explosively drives the hips forward, generating horizontal momentum, which causes the shoulders to flex and the kettlebell to travel in an arc pathway from the thighs to eye level. Proper technique terminates the swing at eye level, not above. Upon the kettlebell reaching eye level, the muscles of the shoulder and upper back must decelerate the bell’s travel and eccentrically resist gravity as the kettlebell returns to the starting position.