Resisted & Assisted – A Strength Training Tool for Sprinters

A Strength Training Tool for Sprinters

By: John Cissik

Originally Published in Techniques Magazine – Official Publication of the USTFCCCA

In 1978 an article by Ozolin was printed in that year's version of Sprints and Relays. In it, Ozolin identified the existence of a "speed barrier" for sprinters, which limited the potential performance of a sprinter, and recommended tools such as resisted and assisted sprinting to push through it (Ozolin 1978).

Assisted sprinting makes the sprinting motion less difficult in the sense that it enables athletes to run at faster velocities than their normal abilities. This may include tools like being towed, sprinting downhill, or sprinting on a high speed treadmill. The thinking is that over time, the athlete will "learn" how to run at greater stride frequencies, which will transfer to non-assisted sprints (Cissik 2005, Faccioni 1995).

Both of these training tools are popular for use with track and field athletes as well as with the speed training of non-track and field athletes. This article will review how these tools should be used and why these recommendations are in place, as well as highlight the literature that examines both training tools.

RESISTED SPRINTING:

Adding resistance to sprinting may be effective at increasing speed, but adding too much resistance may have a detrimental effect on the athlete. In theory, too much resistance will result in the athlete running slower, the athlete may take shorter strides due to the extra weight and may have altered sprint mechanics. (Murray et al 2005; Paulson 2011) All of these may transfer to running without resistance, having a detrimental effect on performance.

Two classic studies demonstrated that too much resistance can alter sprinting kinematics in a detrimental way. Lockie et al (2003), studying rugby and field hockey athletes found that loading sleds with 32.2 percent of an athlete's bodyweight resulted in a 23 percent decrease in running velocity, an almost 24 percent decrease in stride length, a 15 percent increase in trunk lean, and an almost 20 percent increase in ground contact time. In other words, too much resistance resulted in slower sprints, more time on the ground, shorter strides, and an inability to extend the hip during the sprint. These results were also seen by other studies looking at female sprinters and rugby/soccer players (Letzelter et al 1995; Murray et al 2005).

The results of these studies help to demonstrate that with added resistance, more is not better. In addition to the amount of resistance, the type of resistance may have an impact on performance. For example, Cronin et al (2008) studied the impact of five conditions on 30-meter sprints; no resistance, sled resistance (one group had 15 percent of bodyweight, one 20 percent), and vest resistance (one group had 15 percent of bodyweight, one 20 percent). For all conditions, the resisted conditions slowed the athlete, however the sled slowed the athlete more for all resistances. Both the sled and the vest reduced stride length. The sled conditions had the smallest stride length at the beginning of the sprint, but the sled and the vest were equalized by the 25 meter mark. Both the sled and the vest reduced stride frequency. The sled increased the trunk angle (i.e. less upright) whereas the vest resulted in the athlete sprinting in a more upright posture.

As a result of this information, there are several guidelines for the use of resisted sprinting in the coaching literature. These include:

• Resistance should not decrease the athlete's velocity by more than 10 percent (Jakalski 2000, Lockie et al 2003).
• Resisted sprints should last for 15-20 meters and allow for 20-25 meters of free running after the release of the resistance (Coaching Education Committee 2001).
• Proper sprinting mechanics should be emphasized so that bad habits are not learned (Cissik 2005).

While there is information in the literature about the impact of resisted sprinting on kinematics as well as coaching recommendations, the literature establishing its effectiveness is limited. The rest of this section will cover some of the more recent studies looking at resisted sprinting.

Spinks et al (2007) studied eight weeks of sled towing with a weight determined to decrease velocity by 10 percent. Their subjects trained twice per week. The authors had a group that did the same workout without the resistance. At the end of eight weeks of training, the non-resisted group increased their velocity on 15-meter sprints by almost 6 percent, the resisted group by almost 8 percent. Looking at stride length and stride frequency, the unresisted group increased their stride length by almost 1 percent and their stride frequency by approximately 3 percent. The resisted group, on the other hand, improved their stride length by almost 10 percent and their stride frequency by almost 11 percent.

Upton (2011) compared resisted, assisted and traditional sprinting on collegiate female soccer players. All groups trained three times per week for four weeks for 10x20-yard sprints. At the end of four weeks of training, the assisted group improved their ability to accelerate during the first 15 yards of a 40-yard sprint. The resisted group improved their ability to accelerate during the last 25 yards of the 40 yard sprint.

Clark et al (2010) examined the impact of non-resisted, weighted sled, and weighted vest sprinting on division III lacrosse athletes. At the end of seven weeks of training, all three groups improved their 60 yard sprint time; the non-resisted group by almost 2 percent, the weighted sled time by approximately .1 percent, and the weighted vest time by approximately 1.2 percent.

The studies above give some indication that the literature is conflicting about the effectiveness of resisted sprinting. Con Hyrsomallis conducted a literature review in the Journal of Strength and Conditioning Research and concluded that resisted sprinting was an effective training tool, but not necessarily more effective than non-resisted training. One of the challenges with research on resisted sprinting is that most studies are using non-track and field athletes. This makes it a challenge for the track and field coach to interpret the usefulness of the study for his or her situation. This is because non-track and field athletes don't have the training history with sprints that track and field athletes will. In other words, they won't have an equivalent volume, intensity, or mastery of technique that a track and field athlete would. In addition, if there is a speed barrier, it's unlikely that a non-track and field athlete would reach it - which calls into question whether this training tool would even be necessary for them.

ASSISTED SPRINTING

As with resisted sprinting, guidelines for assisted sprinting exist in the coaching literature. Unlike with resisted sprinting, there is less published research to support these guidelines. In general the guidelines for assisted sprinting are:

• Towing should not cover distances greater than 30-40 meters.
• Downhill sprints should not exceed a slope of 2-3 degrees.
• Athletes should not achieve speed greater than 106-110% of their maximum speed.
• Sound technique must be emphasized (Faccioni 1995, Jakalski 2000).

The rationale behind these guidelines is that exceeding them will result in excessive stride lengths that could result in increased braking during sprinting. Athletes that are towed for more than 30-40 meters may have a tendency to allow themselves to be pulled, rather than actively running (Faccioni 1995). In other words the athletes may have a tendency to run at submaximal levels, which defeats the purpose of the exercise.

Sugiura and Aoki (2008) studied male 100 meter sprinters and had them perform 2x50-meter sprints, then another 2x50-meter sprints being towed by a machine. On average, the machine increased their speed by 7.5 percent. To accomplish that, the athletes increased stride frequency and stride length by approximately 4 percent. Contact time decreased by 6 percent while flight time remained the same. This is one of those studies where just looking at the averages is deceptive, looking at the individual results of the individual athletes showed that each responded uniquely to being towed; some increased their stride length, some their stride frequency, some both.

Ebben (2008) studied the optimal slope for downhill sprints using male athletes. In this study, the subjects ran 40-yard sprints at 0, 2.1, 3.3, 4.7, 5.8, and 6.9 degrees of slope. All slopes except 6.9 degrees resulted in faster times, with 5.8 degrees being the best time (6.5 percent faster). As this falls within the 106-110 percent window, it suggests that the 2-3 degree guideline mentioned above might need to be re-examined.

Compared to resisted sprinting, the literature on assisted sprinting is sparse. While there is a great deal of anecdotal information as well as coaching practice, there is little research to support these guidelines. The Ebben (2008) study demonstrates that research may be useful to modifying the guidelines for how to use assisted sprinting. Not only is research on how to use assisted sprinting lacking, but research on its long-term effectiveness is also lacking.

Assisted and resisted sprinting are both popular tools for the speed training of all types of athletes, including track and field athletes. While there is a great deal of anecdotal information on their effectiveness as well as guidelines on their use, the research to support these is sparse and can conflict. Sometimes this is due to the subjects being studied. It is possible, for example, that certain levels of baseline strength and speed are necessary before these tools are truly effective. It is also possible that these tools are not more effective than unassisted or non-resisted sprinting, even so they may provide the variety that an athlete needs to keep his or her training interesting and fun.

REFERENCES

Cissik, J.M. (2005). Means and methods of speed training, part IL Strength and Conditioning Journal, 27(1): 18-25.

Clark, KP., et al. (2010). The longitudinal effects of resisted sprint training using weighted sleds versus weighted vests. Journal of Strength and Conditioning Research, 24(12): 3287- 3295.

Coaching Education Committee. (2001). Coaching Education Program: Level II Course (Sprints, Hurdles, Relays). USA Track and Field, pp. 8-17, 33-42.

Ebben, WP. (2008). The optimal downhill slope for acute overspeed running. International Journal of Sports Physiology and Performance, 3:88-93.

Faccioni, A. (1995). Assisted and resisted methods for speed development. In Jarver, J. (Ed). Sprints and Relays (4th Edition). Mountain View, CA: Tafnews Press, pp. 63-69.

Hyrsomallis, C. (2012). The effectiveness of resisted movement training on sprinting and jumping performance. Journal of Strength and Conditioning Research, 26(1): 299-306.

Jakalski, K (2000). Parachutes, tubing, and towing. In Jarver, J. (Ed). Sprints and Relays (5th Edition). Los Altos, CA: Tafnews Press, pp. 71-73.

Letzelter, M, Sauerwein, G., and Burger, R. (1995). Resistance runs in speed development. In: Jarver, J. (Ed). Sprints and Relays (4th Edition). Mountain View, CA: Tafnews Press, pp. 82-86.

Lockie, R.G, Murphy, A.J., and Spinks, C.D. (2003). Effects of resisted sled towing on sprint kinematics infield-sport athletes. Journal of Strength and Conditioning Research, 17(4): 760-767.

Murray, A., Aitchison, T.C., Sutherland, K, Watt, L, McLean, D., and Grant, S. (2005). The effect of towing a range of relative resistances on sprint performance. Journal of Sports Sciences, 23(9): 927-935.

Ozolin, N. (1978). How to improve speed. In Jarver, J. (Ed.). Sprints and Relays: Contempormy Themy, Technique and Training. Los Altos, CA: Tafnews Press, pp. 55-56. Originally printed in Legkaya Atletika, reference unavailable.

Paulson, S. and Braun, WA. (2011). The influence of parachute-resisted sprinting on running mechanics in collegiate track athletes. Journal of Strength and Conditioning Research, 25(6): 1680-1685.

Spinks, C.D., Murphy, A. J., Spinks, W.L., and Lockie, R.G. (2007). The effects of resisted sprint training on acceleration performance and kinematics in soccer, rugby union, and Australian football players. Journal of Strength and Conditioning Research, 21(10): 77-85.

Sugiura, Y. and Aoki, J. (2008). Effects of supramaximal running on stride frequency and stride length in sprinters. Advanced in Exercise and Sports Physiology, 14(1): 9-17.

Upton, D. (2011). The effect of assisted and resisted sprint training on acceleration and velocity in division IA female soccer athletes. Journal of Strength and Conditioning Research, 25(10): 2645-2652.

John Cissik is the president and owner of Human Performance Services. Cissik has written ten books and multiple articles on strength and speed training in everything. He has worked with all levels and specializes in education, strength training for track and field, and speed/agility training.