Resisted and Assisted Sprint Training: Making Sprinting Harder or Easier on Purpose

Quick Intro

Resisted sprint training adds resistance to a sprint, using a weighted sled, a hill, a parachute or a band. Assisted sprint training, also called overspeed training, does the opposite and makes it easier to reach higher speeds, using a downhill slope or a tow. Both change the demands of sprinting in order to train a particular part of it.

The Idea in Plain Terms

A sprint has an acceleration phase, in which a runner builds speed over the first 10 to 30 meters, and a top-speed phase after that. The two draw on different things. Acceleration depends on pushing forcefully into the ground at a forward body lean, while top speed depends on short ground contacts and fast leg swing.

Each tool nudges one of these:

• Resisted sprinting. A sled, hill or band raises the force needed on each step, which emphasizes the push and acceleration. Heavier resistance changes sprint mechanics more, such as increasing forward lean and slowing the stride.
• Assisted sprinting. A gentle downhill slope or a tow lets the runner move faster than they can unaided. The aim is to expose the legs to a higher stride rate, so the nervous system practices a faster pace.

Common tools:

A Worked Example

A sprint session, offered as an illustration:

Full recovery, often 2 to 3 minutes or more per sprint, keeps each effort fast.

What the Research Shows

A 2016 systematic review by Petrakos and colleagues examined resisted sled sprint training and concluded that it can improve sprint performance, especially acceleration over short distances. Other reviews report that both light and heavy loads have been used successfully, with no agreement on one best load. Light loads that slow the runner by a small amount tend to keep the sprint pattern closer to normal, and heavy loads work more on strength and force in the first steps.

Evidence on assisted sprinting is more limited. Several studies report improvements in top speed or stride rate after overspeed programs, while others show no advantage over regular sprinting, and safety concerns exist with high speeds and towing.

A realistic summary is that regular sprinting remains the core method, and resisted and assisted work are extra tools whose benefit depends on load, distance and the athlete.

Who It Suits

• Sprinters and field-sport athletes who want a faster start.
• Athletes with access to a sled, a hill or a track.
• Coaches seeking variation in sprint training.

It is not suitable as a first step for beginners who have not yet developed sprint technique, or for people with a recent hamstring injury.

How to Use It

1. Warm up thoroughly, because sprinting at full effort strains muscles that are cold.
2. Begin with light loads or gentle slopes.
3. Keep distances short for resisted work, 10 to 30 meters.
4. Rest fully between sprints.
5. Use two sprint sessions a week at most, with recovery days between.
6. Build up gradually and stop if the hamstrings feel tight or painful.

Common Misunderstandings

It is not a substitute for free sprinting.

It is not true that heavier is better.

It is not safe to tow yourself at speeds you cannot control.

FAQ

How heavy should the sled be? There is no agreed answer. Light loads are common for speed and heavier for the push phase.

Are hill sprints resisted training? Yes, uphill running adds resistance without equipment.

Is downhill running safe? Use a gentle slope and stay in control, since steep slopes raise injury risk.

Do I need a track? Any flat, safe surface works.

Where This Comes From

Petrakos G, Morin JB and Egan B, 2016, resisted sled sprint training to improve sprint performance: a systematic review (Sports Medicine, 46, 381 to 400). The overview of assisted sprinting follows reviews of sprint training methods; the evidence is limited.

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Related to: SAQ training, plyometric training and the force-velocity relationship. Exercises include Hill Sprints and Sled Push.