Paulson and Braun conducted a study looking at the impact of sprinting with a parachute on Division II track athletes. Using a parachute to sprint falls into the category of resisted sprinting, which is designed to make the sprinting motion more difficult. The idea is that by making the motion more difficult, the body will recruit more muscle fibers to overcome the resistance and this will eventually carry over to non-resisted sprinting, resulting in a faster athlete. There are a number of resisted sprinting tools; weighted sleds, dragging tires, wearing a weighted vest, sprinting with a teammate attached to you, running uphill, etc.
The first big concern with resisted sprinting is that too much resistance has a detrimental effect on the athlete. When the resistance is too great it dramatically alters the way in which the athlete runs; the athlete’s stride length shortens, stride frequency decreases, the amount of hip extension they produce decreases (this means less force is exerted against the ground), more time is spent on the ground, etc. In short, too much resistance teaches the athlete to run slowly and with bad form – which are not qualities that we want to reinforce in our athletes.
A second concern is that many of the resisted sprinting tools may encourage poor form. For example, when towing a sled or a teammate the weight typically attaches around the athlete’s waist. This encourages the athlete to lean forward while sprinting, which decreases their ability to extend their hip when running. Sprinting with a weighted vest or sprinting uphill would alleviate this problem.
A third concern is that many studies use non track athletes. There are pro’s and con’s to this and it relates to the entire reason for using resisted sprinting in the first place. In a classic paper, Ozolin postulated the existence of a “speed barrier.” His theory was that elite sprinters train themselves to run at certain speeds and are unable to get past this point (his so-called speed barrier). He felt that resisted (and assisted) sprinting methods were necessary to train the athlete to break through the speed barrier. Now, it’s unclear if this really exists. It’s also unclear if this would exist outside of track and field athletes. One could argue that an elite sprinter, who has been training like this for almost 20 years, would have different training needs than a college football player.
When it comes to research, using non track athletes could heavily influence the results because non track athletes may or may not have good, consistent sprinting form to begin with. If they don’t have good form, then research that shows that a given tool negatively effects their form has to be interpreted with that in mind.
Paulson and Braun studied twelve Division II track and field athletes. Their athletes had two sessions, one running 2×40 yard sprints without the parachute (NC) and one running 2×40 yard sprints with the parachute (PR). All sprints were filmed.
There were differences between the two conditions:
• First, the PR sprints were slower. The 40 yard time was almost 4.5% slower than in the NC condition and the average running speed with the parachute was 3% slower than in the NC condition.
• Second, the PR had an impact on joint angles at the point of initial ground contact during the sprint – though none were statistically significant:
o Shoulder angle decreased by 13%
o Elbow angle, knee angle, and ankle angles all changed by around 1%
o Trunk angle increased by almost 23% (i.e. the athlete leaned forward more with the parachute)
o Hip angle increased by almost 6%
• The authors report no statistically significant changes in ground contact time, stride length, or stride frequency though we are never given those numbers to make our own interpretations.
Even though the changes may not be statistically significant, the study shows that the resistance of the parachute alters the running mechanics of the athletes with that increased trunk lean and changes at the hip angle. For this reason, it would have been valuable to see the stride length/frequency and ground contact data. The fact that speed decreased by around 4.5% indicates that this would be an effective tool. Clearly adding resistance to an athlete is going to slow them down, the recommendation is that athletes should not be slowed down by more than 10% or the training tool may be ineffective.
It needs to be kept in mind that this study has limitations. First, as I mentioned above there are pro’s and con’s to looking at track athletes. We can be reasonably sure that they know how to sprint, but the largest application for this training tool will be with non-track athletes. Second, the authors only analyzed one gait cycle and it’s possible that had more been analyzed the results may have been very different. Third, the study does not give the reader any information about the effectiveness of the parachute. In other words, the study tells us that it alters kinematics somewhat and that it reduces speed in the acceptable range, but we aren’t told if using the tool for a period of time will ultimately result in faster athletes.
Paulson, S. and Braun, W.A. (2011). The influence of parachute-resisted sprinting on running mechanics in collegiate track athletes. Journal of Strength and Conditioning Research, 25(6): 1680-1685.
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