In recent years several products have been advanced claiming to have a positive impact on sprint speed. Although many of these devices are supported and endorsed by credible researchers and coaches, for the typical high school athlete such products and their associated strategies, at least in terms of workouts designed for maximum velocity mechanics, are often neither practical nor safe. Far more careful research should be done before any of them are incorporated into the training program of athletes who have, at best, a season-based preparation period.
It is my contention that the greatest gains in improving sprinting speed come not from any single activity, training device, or workout, but from advancing the training age of athletes through the continuity of warm-up activities and drills that become part of each athlete's conditioning routine for each of the sports he or she competes in throughout the year. Thus, the periodization of these drills for speed extends the athlete's core training age from one to as much as three, and it is this dramatic jump in the training age, combined with the I or 2% improvement prep athletes experience just through physical growth and maturity, that enhances sprint performance.
All of the products currently on the market fall into one of two categories: sprint-resisted or sprint-assisted. Some claim that, by contrast use, they enhance sprint performance because they "fool" the central nervous system into recruiting more neurons. It is indeed important to separate workouts that are neural from those that are metabolic, because coaches often confuse these two, and begin to use products thinking that they are effecting a change in motor behavior when in fact they are simply targeting an energy system.
There are also products that claim to improve a specific phase of the sprint model, when in reality they are attempting to effect a change in motor pattern with an inappropriate change in body position. The acceleration chute is one such example.
SPRINT-RESISTED DEVICES: THE PARACHUTE,
SURGICAL TUBING AND THE SPRINT SLED
Nothing attracts more attention from coaches than the appearance in magazines and newspapers of various brightly colored parachutes billowing out from behind a sprinter whose quads appear ready to explode from the force exerted in an attempt to overcome the drag created by air trapped within these assorted avion mushrooms. At Lisle High School we experimented with these chutes several years ago, not because we believed we had come across a brilliant new sprinting strategy, a toy that would bring about major changes within weeks after use, but because we wanted to demonstrate that, for the maximum velocity sprint demands of a typical high school sprinter, the chutes were both impractical and unstable.
The sprint chute was the brainchild of former Soviet sprint authority Ben Tabachnik, who in background, stature, and respect is the Arthur Lydiard of the sprint world. Tabachnik has authored a unique training manual called Soviet Training and Recovery Methods. In the book, co-authored by Rick Brunner, Tabachnik presents the speed chute as a unique means to intensify the training process physically, as well as metabolically and neurologically. Test results, apparently performed in a secluded stadium outside of Moscow, proved that the speed chute was superior to all other devices designed to improve maximal speed, start acceleration, and speed-endurance. Tabachnik notes a dramatic reduction of .2 to .4 seconds in 100 meter dash times, but he was also working with advanced athletes-not beginners.
We found Tabachnik's original chutes, marketed through Atletika, to be expensive, flimsy, and poorly designed. The various connecting cords tangled easily, and the nylon would tear quickly if caught on a fence post or the end of a hurdle. In fact, the nylon chute would often tear long before the velcro waist harness ripped free.
Further, I am convinced that much of Tabachnik's work with the chutes had to be conducted in some of Russia's massive indoor training complexes or skating rinks, where there are no crosswinds to violently disrupt a runner's stride or alter his running path. Although such sudden shifts are appropriate for sports such as hockey and football, they are a disaster for single-direction activities such as sprinting, where athletes are traveling at six to eight meters per second and attempting to apply a force three to four times their body weight for 0.09 to .11 of a second while landing precariously on a three inch-wide spike plate or racing flat. A gust of wind will yank the sprinter all over the place, and such a traumatic oscillation, rather than tearing down a dynamic stereotype, will tear apart a runner's hips, knees, and ankles.
Tabachnik notes that the faster the athlete runs, the greater the drag. Herein is a problem, since the resistance is not uniform for any set length. Current research suggests that to achieve gains in maximum velocity athletes should not be slowed down more than 10% because, as the resistance becomes greater, the ground dynamics begin to change.
There are better means to elicit central nervous system responses. Obviously, one method to make it harder for an athlete to sprint at maximum velocity is to run against the wind. The problem with this technique is that, like the chute, it is difficult to keep a runner within the prescribed 10% window.
Another common resistance device is the sprint sled. Seven manufacturers have created their own versions of this railed platform, and almost all of them are designed to allow weight to be added to further increase the resistance. Conventional sleds are most often used on natural terrain, but the turf increases the drag and provides a less stable surface for the sprinter. I don't advocate the use of these sleds when the training objective is neural rather than metabolic. Again, it may be a great strength gain activity, but I don't recommend it when the workout objective is maximum velocity mechanics.
Hills will provide a contrast training stimulus, but they should never be so steep as to change the dynamics of the sprinter's movements, Also, keep in mind that hill running, although definitely harder than sprinting on flat ground, requires that the mass of the sprinter be raised to a higher level with each step. If maximum velocity mechanics are maintained, the sprinter strikes the ground sooner than would be the case on a flat track. As the incline increases even as little as one or two degrees, the athlete must have enough strength and power to maintain correct maximum velocity mechanics. If the slope becomes too great, the sprinter will not be able effect the tall, stiff knee joint typical of this phase, and angles at the hip and knee will be greater, thereby exerting force over a greater range of motion, a force more typical of the drive required in the starting and acceleration phases.
Pulling a tire seems to be one of the better and more popular methods for keeping the resistance within the 10% range. Athletes should be harnessed to the tire by the shoulders rather than the waist, since harnessing at the waist will also alter the prescribed movement pattern. The tire can be spaced about ten to fifteen meters behind the runner. Any closer and the angle of resistance becomes inappropriate for maximum velocity mechanics. A shorter cord will have a greater impact on positive vertical velocity, which again is more important in the driving phases such as the start and acceleration. If the resistance is too light, weight can be added within the tire.
Though this seems to be the technique most recommended, pulling a tire across a quality all-weather track is one of the best ways to ruin a good surface, and coaches should be mindful of the fact that nothing wears down a polyurethane track as much as the friction of rubber against rubber, which is why the consultants always tells us that PE classes have the potential to do more damage to a petroleum-based surface than runners competing in nine-millimeter spikes!
Coaches have also experimented with using cord systems such as the Ultra Speed Pacer, to create resistance. I will discuss these under sprint-assisted modalities. There are even some motorized devices that will resist an athlete at a set velocity over an established length of track. Years ago coaches experimented with old SST surgical tubing to accomplish sprint resistance. The problem with such tubing, aside from its limitations as to the total length of a run, is that athletes must first run themselves into a resistance zone to get the cable taut, only to experience varying degrees of resistance as the tubing is stretched. I wouldn't advise any of these techniques, because they are unsafe and difficult to monitor.
Ironically, the "safer" methods of achieving resistance are not really appropriate for maximum velocity training. Relatively safe techniques, such as sprinting in sand or in water, although such techniques actually make the task harder, are not appropriate for maximum velocity work. In sand running, ground time is significantly longer. Sand running does not just interrupt dynamic stereotypes in motor patterns, which is the purpose of contrast training; it dramatically alters these patterns. A soft surface provides a totally different stimulus. Because the muscle receptors tune the response time to the surface, sand running does not simulate the explosive stretch/shortening sprinters encounter in the maximum velocity phase.
Remember, the goal of any resistance work for maximum velocity running is to activate the motor units more quickly in order to cause a better neurological adaptation. One of the most important forms of training which leads to improved reactivity of the central nervous system is plyometrics. A plyometric stimulus occurs when a load in one direction, which is greater than that which an athlete normally experiences, is abruptly decelerated and then re-accelerated in the opposite direction or another direction. Of all these methods for providing resistance during maximum velocity sprint training-parachutes, uphill running, running against the wind, running against cables and loads, and running in sand-none provide what I would call the classic plyometric stimulus.
If, as the experts contend, the best plyometric activity is sprinting itself, then the best plyometrics for sprinting would be sprinting while wearing a light weighted vest which slightly increases the mass of the athlete. While running with a weighted vest, the athlete experiences greater loading, which forces the muscles to become more responsive, and creates better intramuscular coordination. Sprinting with a weighted vest provides increased stimulus by increasing the momentum that must be overcome in the vertical direction once the athlete lands-not by increasing the distance over which the body must fall, but by increasing the actual weight of the sprinter. Weighted sprinting also increases the momentum that must be overcome in the horizontal direction.
Some products, such as the weighted thigh wraps, are also designed to interrupt dynamic motor patterns. Dynamic strength and power can be increased by elevating the mass of the limbs. In the case of thigh weights, the sprinter benefits from an added stretch/shortening stimulus.
Before the arrival of the expensive neoprene thigh sleeves, coaches would use football pants with weight bags placed in the thigh pad pockets. Thigh weights will also increase the load on the legs without affecting the coordination and timing of the sprint motor pattern, even when athletes are running at near-maximum speed.
Ankle weights do provide a stretch/shortening stimulus to the hip flexors that cross the knee joint, and since they can impact the muscles which helps to increase negative foot speed, they are acceptable as a very specific kind of resistance training when the weights are kept very low (250- 1 000 grams). However, I would not advise the use of conventional ankle weights, because they lower the mass of the limb that we are trying to move quickly. A proper swing phase in the stride cycle requires that the lower leg be folded tightly to the thigh before the thigh is advanced forward. Making the leg as short as possible right off the ground increases angular acceleration.
Further, biomechanical analysis indicates that sprinters generate seven times as much power at the hip than at the ankle. If the lower legs become too heavy relative to the thigh, as would be the case with ankle weights, they could retard the runner's stride frequency, just as a metronome slows as its weight shifts further from its fulcrum. In addition, the extra weight can cast open the lower leg before the thigh goes through its full range or flexion.
SPRINT-ASSISTED DEVICES: SURGICAL TUBING
AND ULTRA SPEED PACERS
At Lisle we have done quite a bit of research on the effects of overspeed training, and are convinced that two things occur when athletes are sprint assisted: first, the towing procedure "lights up" the central nervous system, bringing into play great numbers of neurons; second, it makes the legs more responsive to ground reaction. By lighting up the central nervous system, I mean that towing alters the timing of the nervous impulse to the effect on muscles. In other words, towing creates some anticipatory firing, and this kind of firing enhances intramuscular coordination. In terms of ground reaction response, we theorize that the increase in horizontal momentum resulting from towing alters the capacity for joint stabilization at the ankle and knee, thereby allowing for a greater transmission of force.
We have observed that sprinters who do repeat 30 and 60 fly or block sprints after two or three repeats of 30- to 60-meter assisted sprints run their unassisted sprints noticeably faster.
For years, we've been documenting this phenomenon, even timing athletes electronically to further support our findings. Our research indicates that this enhanced performance window does not stay open very long, and that performance levels drop back down after five to ten minutes.
Ironically, three high school coaches from Nebraska-Craig McDonald, Steve James, and Tom Kutschkau-observed this same phenomenon while doing sprint-assisted work with surgical tubing. They claim that by using surgical tubing or "bungee cables" athletes can produce unassisted sprints faster than their original capabilities. In effect, they described the process as "breaking down the wall that seems to exist as a person tries to run faster." At the time they wrote their article for Track Technique, they felt that the effect of overspeed towing might be more psychological than physical.
However, other coaches have also observed that this phenomenon does occur in athletes familiar with the technique, but that the effects last a very limited amount of time. Their conclusion was that a "couple of bungee runs" might be an effective part of a pre-competition warm-up.
After numerous discussions with Loren Seagrave on this phenomenon, I am convinced that the neuron recruitment level is definitely increased after overspeed towing.
Over the years, athletes have employed various techniques for lighting up the central nervous system prior to competition. European sprinters have been observed doing speed squats and tempo cleans under the stands right before competition. Platform shoes have been a highly effective means of preparing an athlete for jump competition, because they increase the stretch/shortening in the soleus.
Seagrave notes that the research suggests that, in the case of platform shoes, the effect lasts for about 30 minutes, and athletes return to normal jumping range within an hour. Again, in terms of 30- and 60-meter assisted sprints, I have observed that the effect doesn't last nearly as long it does for vertical jumps; however, Seagrave does not believe that the results of our 30 and 60 meter sprints, even when timed electronically, are sensitive enough to make any accurate predictions as to the duration or intensity of the stimulus. In the case of vertical jumps, a force plate gives immediate feedback. However, even an observable decline in times over 30 or 60 meters, especially when athletes are given full recoveries between training runs, does not provide us with data specific enough to determine precisely how long it takes for this "neural window" to close.
Despite these obvious benefits, unless athletes are highly advanced in training age, I would avoid this kind of training. If an athlete has an unstable motor pattern, sprint-assisted work will only make his mechanics worse by magnifying errors. Unless coaches have a clear method for keeping athletes within the 10% zone, runners can generate so much speed that they begin braking actions in an effort to avoid falling forward. As soon as athletes initiate any kind of braking action, they are being taught to stay on the ground longer, and their bodies quickly adapt to this incorrect stressor.
Overspeed training using surgical tubing is dangerous, and I do not advocate the use of any kind of elastic cable in attempting to assist sprint performances. Not only is there an obvious risk of having the cable snap back on the runner especially if the end slips out of a partner's hand, but because the tubing can't be released from the sprinter's body, as it returns to its pre-stretched position, athletes must often step gingerly in their coast and-stop phase to avoid getting tangled. It is not uncommon to see sprinters forced into awkward and precarious movements at the end of a tow in an attempt to avoid tripping over long sections of uncoiled cable caught between their legs.
In addition to being a safety problem, surgical tubing and elastic cables can often place inappropriate loading on the central nervous system. Elastic cables, for example, have only a small range where the resistance is right. As a sprinter stretches the cord, the resistance increases. When the cable is very taut, athletes are simply pulled to maximum velocity thus creating an artificial stimulus. Further, if a sprinter is actually towed well beyond the 10% window, he or she will begin to initiate braking actions to avoid falling, and because these actions cue the nervous system to increased ground contact time, they actually inhibit correct maximum velocity mechanics.
THE ULTRA-SPEED PACER
The Ultra Speed Pacer uses thin inelastic cord and pulleys to achieve an assisted sprinting stimulus. It is a surprisingly simple, safe, and controllable device that tows the athlete at a speed twice that of the outgoing runner. Basically, the outgoing runner controls the degree of pull at a 2 to I ratio, which means the 10% stimulus window can be monitored more carefully by checking the speed of the runner doing the towing. If the sprinter feels he is being towed too fast, he simply slaps the pulley from his waist harness. There is also a velcro safety strip that can be adjusted to release if the load on the towed runner becomes too great.
I believe that Ultra-Speed Pacers are expensive for the kind of technology you can find in almost any hardware store: two pulleys, a plastic extension line reel, and 300 feet of smaller gauge nylon cord. However, the inventor is a genius. I wish I had thought of something like this years ago.
There are other forms of assisted running which are safer and less expensive, such as sprinting with the wind and sprinting downhill.
Unfortunately, it is impossible to control either the velocity or availability of wind, and, therefore, this technique has major limitations. Further, since the wind velocity is never constant, it is hard to keep sprinters within the 10% window.
Downhill sprinting provides a very good horizontal plyometric stimulus. As long as the slope is no greater than I per cent, even inexperienced athletes can run with optimum sprinting mechanics. Remember that the elevation of the center of mass is greater at takeoff than it is at touchdown, and this means that the vertical distance through which the center of mass travels also increases. Thus, athletes sprinting downhill experience greater vertical velocity.
Because decline sprinting is an overspeed stimulus in both a vertical sense as well as a horizontal sense, it places a great demand on the nervous system. It is a safe and reliable form of assisted training, provided that the grade remains low and that athletes stay within their 10% zone.
The key is to choose a resisted or assisted method that is best for maximum velocity mechanics. Some techniques arc easier to monitor than others. I recommend that coaches consider using a football field for contrast work with inexperienced athletes. The "crown" on a football field is usually about a 1% grade. If athletes sprint from one sideline to the middle of the field, they experience some resistance. This kind of uphill running is not plyometric, because there is no increased loading on the body and no increased horizontal or vertical velocity, but once the athlete reaches the middle of the field and sprints "down" to the other sideline, this slight grade does produce a plyometric stimulus that is usually within the 10% zone.
At Lisle I have been experimenting with a system I call plyosoidal running. I believe it is one of the best methods to apply a more constant plyometric stimulus that is both horizontal and vertical. I would like to say that I've been the first to come up with this concept, but international sprint authority Remy Korchemny has also been employing a similar technique he simply calls plyometric sprinting. Korchemny places on a track a series of three-inch-high boxes set approximately one and a half meters apart. Athletes sprint for thirty or sixty meters, placing each right or left stride on the top of the box, the opposite foot landing back on track level.
I prefer to use sections of a replaced polyurethane long jump runway. Unlike the boxes, these sections are far safer to land on, give the same response as the level attack, and can be stacked if I choose to increase the vertical component. I can place these sections on the track so that athletes drop to the original surface on the same leg, or I can extend the sections, allowing athletes to take two strides on the higher sections of track, which means that every third stride drops an alternate leg to regular track level.
Plyosoidal running, a plyometric activity which alters the stimulus of regular sprinting, changes the athlete's typical sinusoidal curve. In other words, the explosive stretch/ shortening, which occurs at much higher speeds than it does during typical displaced jumping activities, activates more motor units, thereby resulting in greater force output. I believe plyosoidal running has some great advantages, but it is topic for a whole new clinic session.
Combining sprint-resisted and sprint-assisted activities within a training session and then finishing with regular maximum velocity sprinting, a system known as contrast training, is a unique way to target the sprinter's neuro-motor pattern. However, keep in mind that you can't introduce this kind of training, do it a few times, and then think you've evoked a training stimulus. Contrast train two times a week for a six- to eight-week period. Never do back-to-back sessions, because the nervous system takes longer to recover than the cardiovascular system. Allow at least 72 hours for recovery.
The purpose of this discussion is not to discourage coaches from investing in training devices designed for sprint-resisted and sprint-assisted sequences. I still use speed chutes for acceleration training, and short sections of surgical tubing for in-place sprint drills. Further, I do not wish to suggest that there is something wrong with workouts such as uphill running, sand running, or sled pulling, which are great ways to increase strength and power. All of these play important roles in the sprint program, but some activities, based on time of force application, joint position, intensity, duration, are more metabolic than neural and if the goal of a particular workout is maximum velocity mechanics, then coaches must be careful to make certain that the training
FROM: TRACK COACH 144--SUMMER 1998