It’s no secret that we at SPARC love kettlebells. We feature a variety of kettlebell resisted movements on a daily basis. One of our favorites is the kettlebell swing. This seemingly simple exercise packs a punch when it comes to total body tension, force development, and conditioning.

There are some differences in how a kettlebell swing can be performed. During a “Russian” kettlebell swing, there is less knee flexion and more emphasis is placed on hip flexion/extension, called a “hip hinge.” This is similar to the hip position achieved during a deadlift or vertical jump. An “American” swing employs knee flexion similar to a squatting movement. At SPARC, we teach the Russian kettlebell swing due to its unique benefits for strength and power development. Here’s what the research says about kettlebell training, especially the swing:

 

Kettlebells can make you strong and powerful:

Based on 5 studies, kettlebell training has been shown to improve strength and power in both male and female subjects. These 4 studies took subjects through a 6-8 week kettlebell training program, typically with weights between 8 and 16kg. At the end of these interventions, improved strength was recorded through 3RM Bench Press and 3RM Back Squat tests. Power was improved and measured by clean and jerk and vertical jump.

Of note is that fact that the programs utilizing heavier weights (16kg kettlebells) showed greater improvements in strength. This highlights the importance of progression with weight. Performing the same exercise with a constant weight will not produce as many strength gains as progressing to heavier loads.

When compared with traditional strength movements, Olympic lifting provided greater improvements in strength than those of kettlebell training. However, the Olympic lifting protocol throughout the studies did not limit the weight used for training, or the volume. In other words, the traditional lifts were performed with greater than 8-16kg weights, and thus would naturally provide a greater stimulus. The improvements in power and rate of force production were equal between Kettlebells and Olympic training. This suggested that Kettlebells may be a better tool for power training than strength training, but more standardized research must be completed.

Kettlebells can make you conditioned:

Of 4 studies, 3 found that Kettlebell training can achieve greater than 60% VO2max values, which falls into the “vigorous” category of exercise according to ACSM’s standards. This suggests that kettlebell training can be a valid form of cardiovascular training.

At SPARC, we condition with kettlebells by utilizing time or rep-based intervals. For example, perform 20 seconds of kettlebell snatches, then rest as for 20 seconds, and repeat for 10 minutes. Similarly, you could perform 10 kettlebell swings, rest only as needed, then perform 10 more repetitions. Repeat for 5 minutes.

Kettlebell training can be more applicable to daily movement than other forms of exercise:

3 studies examined muscle activation, spinal loading, lumbar rotation, and ground reaction forces during kettlebell training. These studies found that spinal loading increases during the “bottoms up” position of kettlebell training, when the handles are below the bell. Spinal loading through weight training is crucial for stimulating bone remodeling and improving bone mineral density. This shows that kettlebell training has the potential to improve bone health. However, the studies also found that spinal loading was shown to be greater in standard lifts such as the back squat, most likely due to the greater load placed on the back.

The typical exercises we use for improving spinal loading and bone health are:

  • Bottoms Up Carry
  • Bottoms Up Press
  • Pistol Grip Carry

Next, the studies found that kettlebell training has a higher percentage of horizontal force transfer than traditional forms of weight lifting. Most sports and athletic movements require force transfer through the horizontal plane, so improving horizontal force production can carry over to improved performance. Kettlebell swings also showed increased activation of the hamstrings (especially medial hamstrings) and gluteals during eccentric loading. Because the medial hamstrings and gluteal muscles play a huge role in explosive movements, like sprinting, these findings show that kettlebell training may be superior for improving specific sport performance.

Kettlebell training safety concerns:

Measures of ground reaction forces (GRF) during the kettlebell swing found that it has the lowest magnitude of GRF compared to jump squats and heavy back squats. GRF are a concern due to the potential for joint injury or repetitive stress. If you suffer from knee or ankle joint issues, such as osteoarthritis, heavy kettle swings may be a safer option than squatting.

Finally, these studies found that lumbar rotation was greater during kettlebell swings, with shearing and compression forces highest during the beginning of the swing (with the bell under the body and behind the hips). This may indicate that kettlebell training is not ideal for individuals with chronic lower back conditions.

Kettlebells are a versatile tool for improving total body strength, power, and flexibility. The science shows that the kettlebell swing deserves to be placed among the squat, deadlift, and power clean for improving physical performance.

 

Sources:

http://journals.lww.com/nsca-scj/Abstract/2014/06000/The_Role_of_Kettlebells_in_Strength_and.7.aspx