Study reveals differing effects of running 'with assistance' versus 'against resistance'

Two specialized training techniques—resisted and assisted sprint training—both lead to faster sprint speeds in high-level female soccer players, reports a study in the October issue of The Journal of Strength and Conditioning Research, official research journal of the National Strength and Conditioning Association (NSCA). The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.

However, the effects differ depending on acceleration distance, suggesting that the choice of speed enhancement techniques should be sport-specific. For sports like soccer that require "first-step" quickness, assisted sprint training is more likely to produce the desired result, according to the report by David E. Upton, Ph.D., of Texas Christian University, Fort Worth.

Differing Effects of Running 'With Assistance' versus 'Against Resistance'

Dr. Upton compared the effects of different sprint training programs in 27 NCAA Division IA female soccer players. After initial testing of 40-yard sprint speed, the women were randomly assigned to three different sprint training groups. One group received resisted sprint training, in which they ran against resistance. Another group received assisted sprint training, in which they ran with assistance.

The resisted and assisted drills were performed using specially designed harnesses, which allowed trainers to either pull against or pull with the athletes as they ran. The effect is comparable to running uphill (resisted training) or downhill (assisted training). Both techniques have been reported to improve sprint speeds, although the effects on performance have been inconclusive.

A third group received traditional sprint training, with no resistance or assistance. All training programs lasted for four weeks (twelve sessions).

Both resisted and assisted spring training led to significant increases in sprint speed. Overall 40-yard speed increased by 0.08 meters per second per meter with assisted training and 0.06 meters per second per meter with resisted training. For athletes receiving traditional sprint training, speed was unchanged.

Although the assisted and resisted training methods produced similar improvements in 40-yard sprint speed, the split times showed some significant differences. The assisted training group had significant increases in speed from 5 to 15 yards, compared to no change in this distance in the resisted training group.

In contrast, the resisted training group had increased speed from 25 to 40 yards, compared to no change in the assisted training group. The assisted training group had increased acceleration during the first 15 yards of the 40-yard sprint, while the resisted training group had increased acceleration during the final 25 yards.

"That is, the training modalities impact maximal velocity differentially as a result of their net effect on the rate of change in velocity, or acceleration, over the total distance covered," Dr. Upton explains. The improvement in initial quickness with assisted training may reflect "enhanced neuromuscular facilitation" in response to training at faster-than-normal (supramaximal) speeds.

From a practical standpoint, the choice of resisted versus assisted training may depend on the requirements of the individual sport. In soccer, initial acceleration is an important key to separating from or closing on an opposing player.

Thus assisted sprint training may be an effective way of developing "first-step quickness" in soccer players, whereas resisted training would be a good choice for a football wide receiver who needs to turn on the speed when running downfield. "Strength and conditioning professionals might consider using a combination of protocols, perhaps switching off between different days," Dr. Upton adds. "The key is to recognize the benefits of each technique and to use them in achieving sport-specific training goals."