Restoring Speed After A Sports Injury

Before returning to sprinting after a sports injury, it is essential to progressively regain strength, agility, and speed under the guidance of a qualified sports physical therapist. To prepare for a return to sprinting, a physical therapist begins with isometric and eccentric strength training followed by plyometric and agility training before progressing to a sprint training program. Returning to sprinting is an objective in the later stages of rehabilitation for lower extremity injuries. It is critical that athletes achieve interval sprinting at top speed in the controlled, predictable environment of the physical therapy clinic before engaging in competition and returning to sport. 

The Impact of Sprinting on Your Muscles and Tendons

Before returning to sprinting after a sports injury, it is essential to progressively regain strength, agility, and speed under the guidance of a qualified sports physical therapist. This is because time away from a sport due to injury reduces the physical capacity of tissues. Faster running speeds increase muscle force, tendon load, and loading on bones, so an athlete’s injured leg must be prepared for the loads to be placed on the tissues, muscles, and bones of the lower extremity through a progressive strengthening program.

As running speed increases, muscle force increases. For example, hamstring forces reach nearly eight times the individual’s body weight and calf forces reach seven-to-eight times body weight during high-speed running. Faster running speeds also increase tendon loads and increase the rate of loading, which is the amount of force and how quickly the force is applied to the tendon.

Tendons behave as springs through a stretch-shorten cycle. During running, as impact occurs, the tendon absorbs the energy, compresses, and then recoils, releasing some of the stored energy. Higher loading rates, as when sprinting, lead to more tendon contribution and can heighten the risk of injury. For example, as running speed increases, there is an increase in the contribution of the Achilles’ tendon compared to the soleus and gastrocnemius muscles (calf muscles).

Bone loading also occurs as speed increases due to the effect of muscular contractions on internal bone load. The increase in compressive loads on bone at faster speeds is illustrated by the fact that compressive forces on the shin bone when sprinting were equivalent to 6 to 14 times the individual’s body weight.

Restoring Speed during Rehabilitation

Rehabilitation after a lower extremity injury initially involves cross-training activities to maintain strength and overall fitness in the athlete without placing undue stress on the injured area. Cross-training activities that are commonly used for injured athletes and runners include aqua jogging in a therapeutic pool, walking on an elliptical, or using a stationary bike.

To prepare for a return to sprinting protocol, the physical therapist initially introduces isometric and eccentric strength training followed by plyometric and agility training before progressing to a sprint training program. Isometric and eccentric strength training are used to rehabilitate muscles and tendons and prepare them for the loads placed on them upon return to sprinting and sport. Isometric training involves muscles producing force without any external movement by maintaining a specific joint position while resisting a specific load or exerting force against a stationary object. Isometric training has been shown to effectively manage pain, enhance tendon stiffness, and increase strength more than heavy resistance training alone.

Eccentric training involves lengthening of muscles while resisting a given load and can include the use of free or stack weights. Eccentric training increases a muscle’s fascicle length, which is associated with a lower risk of muscular injury. Plyometric training involves a rapid stretch-shortening muscle contraction cycle, which closely replicates how muscles work in most sports. Plyometric training generally isn’t introduced until the later stages of rehabilitation.

Agility is the ability to change direction rapidly while maintaining speed and precision and is often in response to a stimulus (anticipation of or reaction to the stimulus). Agility requires sufficient muscle and tendon strength, technical skill, and motor control and is demanded of most athletes. Agility training can involve ladder and cone drills, lateral bounding, figure eights, reactive and mirror shuffles, and plyometric jumps.

Return to Sprinting Protocol

Returning to running and sprinting is an objective in the later stages of rehabilitation for lower extremity injuries. It’s important that athletes achieve interval sprinting at top speed in the controlled, predictable environment of the physical therapy clinic before engaging in competition. First, the athlete should receive a musculoskeletal screening from the therapist to assess any impairments and deficits as well as determine readiness to begin the return to speed protocol. Initially, the athlete must complete a four-week return to jogging program that involves walking-jogging intervals that progressively reduce time walking and increase time jogging, up to thirty minutes of jogging. This builds an aerobic base from which to engage in more intense sprinting and allows for any corrections on running gait form and mechanics.

There are three stages to the return to sprint progression. The first stage begins after the four-week return to jogging program and once the athlete has passed a hamstring and quadriceps test in which the injured leg achieves 70% of the uninvolved side’s strength. The goal is to rebuild work capacity for higher intensity runs and improve overall fitness, running at 50% of max effort.

Stage 2 begins once all strength and functional testing of the injured leg achieves 80-85% of the uninvolved leg and full passive flexion is restored. The goal during this stage is to build sport-specific skills with repeated sprinting ability, running at 75% of max effort. As the intensity of runs increases, resting periods also increase and the focus is on correct running technique and sprint mechanics. The athlete is building repeated spring ability during this stage, which is the ability of the athlete to recover and maintain maximal effort during subsequent sprints. Finally, stage 3 begins when strength and functioning testing reveals the injured leg is operating at 90% or better than the uninvolved leg with the goal of achieving maximum effort, normal running and sprinting mechanics, and preparation for return to sport.

Returning to sport requires a progressive strengthening program, agility training, and a guided return to sprinting protocol. Work with our sports physical therapists to prepare effectively for your return to sport!