Which Muscles do Kettlebell Swings Work

Kettlebells are very versatile and can be used for a whole range of exercises. You can get a full body workout using just a kettlebell. Kettlebell swings are a high intensity exercise which are great for cardiovascular fitness, strength and power, calorie burn whilst having low impact on the joints.

How to perform a kettlebell swing:

1. Place the kettlebell on the floor in front of you
2. Stand with your feet shoulder width apart, knees slightly bent. Do not assume the squat position
3. Assume a hip hinge position (push hips back) keeping your back straight
4. Engage your arms, shoulders and lats
5. Take hold of the kettlebell handle with a pronated (overhand) grip
6. Swing the kettlebell behind you, between your legs. This will help to create momentum
7. Thrust your hips forward and engage your glutes and core as you raise the kettlebell up in front of you to shoulder height, keeping your back straight
8. Let the kettlebell swing back down between your legs and repeat

How important is form when performing kettlebell swings?

It is crucial that you get your form right when performing kettlebell swings. Poor form can result in injury. Injury to the shoulders is a common problem due to swinging the kettlebell using the shoulders and arms rather than letting your hips force the momentum. Remember, kettlebell swings are a full body exercise with emphasis on the glutes, hamstrings and core. Back injury can occur if the back is not positioned properly whilst the exercise is performed. It is also important to start with lower weighted kettlebells and as you become more experienced and gain strength, gradually increase the weight.

There are number of muscles worked whilst performing kettlebell swings, particularly the back of the body (posterior chain):

1. Glutes - The glutes are responsible for the force of the hip extension movement which generates the power needed for the arms and shoulders to swing the kettlebell forwards.
2. Quadriceps - The quads are responsible for knee extension. As you swing the kettlebell upwards and straighten your legs, your quads engage. Similarly, as the kettlebell swings back downwards, the quads engage again as the knees bend. 
3. Hamstrings - The hamstrings are responsible for flexing the knee. Keeping straighter legs will activate the hamstrings more due to the length of the muscle fibres. When the muscle is stretched it expresses greater strength and works the tissue more effectively. This is apparent during the hip hinge movement of each swing.
4. Trapezius and Rhomboids - The traps stabilise the shoulder blades and upper back. The rhomboids also play an important role in shoulder and scapula (shoulder blade) movement and stability. By keeping your back straight and shoulders back whilst holding the kettlebell, your traps and rhomboids are engaged.
5. Spinal Erectors - The spinal erectors are responsible for straightening the back which is essential for good form whilst performing the exercise. If these are not engaged, the spine will round leading to extra stress and possible injury of the lower back.
6. Abdominals - The abdominis and oblique muscles stabilise your core and prevent the spine from hyperextending. Similar to the spinal erectors, trapezius and rhomboids, they will be engaged throughout the whole movement, but  the abdominals will be used most to prevent hyperextension of the spine at the top of the movement where the momentum of the kettlebell is at its greatest.
7. Deltoids - The deltoids are responsible for moving your arms in different directions and stabilising the shoulder joint. The anterior (front) and lateral (side) deltoids are engaged when lifting the kettlebell out in front of you, and again to control the lowering of the kettlebell.
8. Forearms - The flexor digitorum profundis and flexor pollicis longus muscles are responsible for grip strength. Simply by gripping the kettlebell handle, these muscles are engaged and are essential for performing the exercise without dropping the weight.
9. Calves - The gastrocnemius and soleus muscles, like the hamstrings, help to flex the knee. As you swing the kettlebell upwards, the momentum pushes you forwards, so in order to keep your balance, you tense your knees in a slightly bent position, engaging the gastrocnemius and soleus to prevent the body from falling forwards.

Kettlebell swings are a great exercise for anyone, from beginners to professional athletes. They provide an intense workout that works on the explosiveness of almost all the muscles in the body. The explosive movements allow you to recruit more muscle fibres which ultimately leads to greater muscle development (provided that you have a good diet). The explosiveness of the exercise is also great for developing speed, so kettlebell swings are particularly ideal for athletes and sportspeople. Like any strength training, correct form is vital to minimise the risk of injury but by perfecting the movement with lighter weights initially, you will be able to progress more safely to heavier workouts in no time at all!