Pulling a weighted sled can be an effective way to increase acceleration speed. One challenge of many traditional sleds is that they can be loaded with a lot of weight, however research suggests that approximately 10% of bodyweight is most effective for creating an overload that can result in faster acceleration times. Using a traditional sled is great for increasing strength because it is easy to add a lot of resistance and challenges the muscles to focus on concentric (shortening) muscle actions to overcome the inertia of the mass of the sled (this is the benefit of heavy sled training – the focus is on muscle shortening; too much weight can overload the muscle during the eccentric or lengthening phase of muscle action. Heavy sled training is great for working on lower body strength gains).
The SKLZ SpeedSac is awesome because it is designed specifically to work on speed so it is not necessary to overload with too much weight. The SpeedSac is thick vinyl so it can be used on grass, turf, wood flooring or dirt without making marks or digging grooves into the surface (like what happens with the runners of a traditional sled).
The SpeedSac has a comfortable belt which wraps around the waist and can be help firmly in place with velcro. It is easy to change the amount of resistance in the SpeedSac by adding a weight plate or (my favorite) Sandbells by Hyperwear. Using a light resistance helps improve the speed of foot turnover while providing just enough resistance to help increase the amount of force the legs are sending into the ground during a sprint. The versatility of the SpeedSac allows it to be used during forward runs, backpedals, lateral shuffles and crossover steps.
If you’re looking for an easy-to-use tool that can help improve your speed, power and acceleration definitely consider giving the SKLZ SpeedSac a run.
What I liked:
• Small, compact, easy to transport.
• Doesn’t dig into the ground or mark up a gym floor.
• Easy to add or remove weight.
• Belt is comfortable, easy to adjust and allows to be used in multiple directions.
What could be improved:
• While it’s easy to add weight, it would be nice to have a zipper-type top so that weight doesn’t slide out when changing the direction of the SpeedSac (this isn’t a big deal, but a minor tweak that would be nice).