Cardiovascular exercise elevates the heart rate for a sustained period, improving the efficiency of the circulatory system. Cardio activities exist on a spectrum defined by the physical force exerted on the body’s joints and muscles. Training is categorized as low-impact or high-impact based on this stress. Understanding high-impact cardio (HIC) is useful for determining if this training style aligns with your fitness goals and physical condition.
The Biomechanics of High Impact
An activity is defined as high impact when both feet simultaneously leave the ground during the exercise cycle. This moment of flight, followed by landing, generates a substantial ground reaction force (GRF) that travels up through the body. The GRF is the force exerted by the ground on the body, equal in magnitude and opposite in direction to the force the body applies to the ground. During high-impact movements, this vertical force can reach up to 2.5 times a person’s body weight upon foot strike.
This high vertical load creates a distinct “impact peak,” differentiating HIC from low-impact activities where one foot remains in contact with the ground. The repetitive transmission of this force through the skeletal system and joints is responsible for both the unique benefits and the increased risks of this exercise style. The body’s tissues respond to this mechanical strain by adapting and becoming stronger.
Common High Impact Exercises
Many well-known fitness activities fall under the high-impact category because they involve the defining moment of flight. Running is the most recognized example, as each stride includes a phase where both feet are airborne before landing. This repeated impact, especially on hard surfaces, subjects the lower body to significant mechanical loading.
Jumping rope is another common HIC activity, where continuous short hops rapidly elevate the heart rate while generating repetitive impact force. Exercises classified as plyometrics, such as box jumps and depth jumps, are designed to maximize this ground reaction force for muscle power development. Certain aerobic dance moves, like vigorous leaps or jumping jacks, also involve the necessary flight phase and subsequent high-force landing to be considered high impact.
Who Should and Should Not Use High Impact Cardio
High-impact cardio offers specific physiological advantages that attract many healthy individuals. The mechanical stress delivered to the bones during HIC encourages the body to improve bone mineral density. This is beneficial as a preventative measure, helping to slow the natural rate of bone loss that begins around middle age. HIC activities also require more muscular effort to lift the body against gravity, often resulting in a superior calorie burn in a shorter duration compared to lower-impact alternatives.
However, the force that benefits bone health makes HIC unsuitable for certain populations. Individuals with pre-existing joint conditions, such as advanced arthritis or degenerative joint disease, should opt for low-impact training to prevent exacerbating joint degradation. Similarly, people recovering from musculoskeletal injuries or those in later stages of pregnancy are advised to avoid HIC. The repetitive, high-magnitude loading increases the risk of acute and overuse injuries in those whose joints, ligaments, or tendons are compromised.
Techniques for Injury Prevention
Once an individual decides that high-impact cardio is appropriate, several practical steps can mitigate the risk of injury. A thorough warm-up is important, preparing the muscles and joints for intense exertion by increasing blood flow. This should include dynamic stretches, such as leg swings and torso twists, rather than static stretching.
Focusing on correct technique is an important element of safety, especially during explosive movements like jumping. Landing softly, with a slight bend in the knees and engaging the core muscles, helps absorb the vertical ground reaction force more efficiently. Wearing supportive footwear that provides adequate cushioning and stability also helps manage impact forces. Finally, varying the types of cardio performed, known as cross-training, prevents overuse injuries by avoiding repetitive strain on the same muscles and joints.