Acceleration is king for high level sports performance. It's typical in field-based sports for athletes to intersperse repeat short-distance sprints throughout a match. These shorter distance accelerations are dependent on the athlete's abilities to generate large amounts of horizontal force in a short amount of time.
In a recent study, researchers wanted to study the effects of very heavy sled training on horizontal force output for short distance sprints.
Sixteen amateur soccer players were assigned to a very heavy sled load group (80% body mass sled load) or a control group (unresisted sprints). The soccer players participated in 16 sessions of 10x20-meter sprints over the course of eight weeks.
The results showed that very heavy sled training was effective for increasing maximal horizontal force production and mechanical effectiveness compared to the unloaded group. There were also moderate and small improvements in 5-meter and 20-meter sprint performance for the heavy sled training group.
Horizontal Force Production
The results from this study are consistent with previous research showing that other horizontal loaded training movements like the hip thrust and horizontal loaded plyometrics can improve short distance sprint performance. As well as with previous research showing that heavy sled loads can improve horizontal force production and short distance sprinting.
Some reasons why researchers think that these movements can increase horizontal force production and sprint performance include increased strength/power in muscle groups specifically used for horizontal force production and increased biomechanic efficiency during the acceleration phase of sprinting.
VHS Training offers a few advantages including increased horizontal force production, mechanical effectiveness, concentric contraction (this type of contraction doesn't elicit the same muscular damage as eccentric contractions, resulting in decreased soreness and faster recovery times), and less axial (vertical loading as when holding a bar during a Back Squat) loading than traditional strength training methods. In fact a study on a NCAA Division-I quarterback with disc herniation issues where heavy sled pulls replaced the Back Squat showed significant improvements in the quarterback's speed. This shows potential for the use of heavy sled training as a safe alternative to traditional spinal loading strength training movements to improve strength, speed and sport-specific horizontal force production.
How to Use Very Heavy Sled Training
The initial study used 80% of the soccer player's body mass to prescribe loads. For a 165-pound athlete this would be equivalent to 132 pounds. One method that athletes can use for an even more specific loading protocol would be to base the load off of their lean body mass if they have access to a reliable form of body fat testing. Using a 165-pound athlete with 15% body fat as an example, this would equate to 140.3 pounds of lean body mass. In this second example an 80% load of their lean body mass would be the equivalent of 112 pounds.
Here's an example workout that you can do twice per week.
Very Heavy Sled Push
- 10x20 meters with 2-3 minutes of rest between sets
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