With some cutting and pasting, here are some of the major things Charlie pointed out concerning sprint technique. Everything below are in Charlie’s own words from the 2002 site.
LEG MECHANICS
I can only point out common problems. The most common technique problem is pushing or driving too hard. The point of getting stronger is to make the sprint actions easier. Think of a spinning bicycle wheel. If you want the wheel to go faster, would you push along it or would you strike it in a short action after accelerating your hand first? It’s the same with ground contact. As you sprint, the ground is moving backwards under you (relatively). You must accelerate your foot before foot strike so that it is moving backwards faster than the ground is moving backwards (negative foot speed). The contact times become shorter as speed improves. One clue that may help you decide if you’re pushing too long on the ground, the soreness you experience will be concentrated lower in the hamstrings.
As long as you are relaxed, sufficiently flexible, and don’t try to cut off the stride by fighting for frequency, full extension should happen automatically. The desired actions are the result of preparatory actions, ie pump the arms with the emphasis on the DOWN stroke and the backward forces will be there-- same thing with the legs- the sprinter only
really feels the down action, as the proper backward action happens over such a short duration that it can barely be sensed, and any attempt to emphasize the backward motion will result in a breakdown of form…
[When stepping over and down] The foot must be pre-tensed. This is accomplished by cocking the big toe up and pointing the ball of the foot towards the ground. This action will activate the dorsiflexers but I’m not suggesting pulling the whole foot up! There is also some confusion about when to prepare the foot for ground contact. One “Guru” has even suggested leaving the foot pre-tensed at all times! Of course, this would have the unfortunate effect of eliminating the final extension around the ankle at take off. The best time for foot preparation is just as the foot is passing over the support knee. . Any attempt to “toe up” earlier may result in a limitation of automatic ankle extension at the end of ground contact- “Toe up” any later and it may be too late to effect an active landing.
The toe-up position is required PRE-GROUND-CONTACT to create elastic conditions in the foot. The ball of the foot is moving down just prior to foot strike as the knee straightens. At GC the foot turns over and the toe extends naturally.
The idea of “running on your toes” has confused a lot of people over the years. Yes you want to cock the big toe up before foot strike but the ball of the foot is moving down towards the track during the leg-straightening phase, particularly if you have excellent hip height. The foot is fully extended at the end of the contact phase with all top sprinters- far beyond the average.
Stepping over the support knee just means that the swing leg is sufficiently folded that its foot passes the support leg as it moves forward at a point at or slightly higher than the support knee. Stepping over" is also a function of flexibility. the top athletes do have a shorter lever during the recovery phase. Stepping over at the knee is the minimum level.
Shortening the lever in the recovery phase isn’t to reduce swing time, it’s to reduce the work load on the hip flexors.
If the sprinter- ANY SPRINTER, doesn’t step over the support knee, whether through conscious action or not, his form will turn to crap in a matter of steps. Those steps- the athlete struggles with knee lift that would otherwise be automatic, arches his back and/or leans back in compensation, the hip drops causing a loss of ground forces. Ground contact forces are key- BUT they are dependant on set-up in advance of foot-strike. This is the reality with which every world-class sprinter is familiar, and coaches ignore at their peril!
The action feels primarily up and down at top speed and there are many ways to describe the action, but what can’t be done is to just rely on dumb luck to achieve the correct technique- or to maintain it at all times even after you get it. The solution may be therapy, training load adjustments, or cues. When you step down from a sufficient height, the backward componant occurs automatically in a time frame that is too short to think about, so in that respect, it is “active” but requires no conscious input.
The downward movement at full speed is a paradox. although the emphasis of the athlete is only on stepping down, if he is sufficiently powerful, he will be higher over the ground. From a greater height, the leg has time to begin swinging backwards more, so that foot-strike occurs closer to, but still slightly ahead of the CM. Although the emphasis is on a downward movement, and the extremely short ground contact time does not allow for this to be sensed, the actual landing vector becomes more backwards and less downwards as performances rise. This is a fundamental flaw in the Harvard study. They seem to have worked backwards from an assumption that Michael Johnson was the fastest runner of the top people reviewed, such as Mo Greene and Frankie Fredericks. In fact, these athletes showed HIGHER peak velocities in races, and this is precisely why they generated lower vertical forces than Michael into the track (though ALL forces remain terrifically high). This is certainly NOT to suggest that anyone try to generate “negative foot speed” before landing. Anyone generating such a sensation would be landing farther ahead of the CM and would have to have a lower hip position, and therefore lower speed. Negative Foot Speed is the by-product of proper mechanics and hip height- not a deliberate emphasis on pulling the foot back. I have attempted to describe the sensation of proper mechanics in Speed Trap.
The greater the sensation of “pawing action”, the lower the hips are- therefore the slower the athlete. (This doesn’t mean that the action is not back as well as down, it’s the way the action takes place.)
Just because there is no sensation of pawing does not mean that the foot lands behind what I would call Bottom Dead Center or directly under the hip point. The foot does strike slightly ahead of this point at top speed (closer and closer to BDC as hip height increases.)
Newtonian Lesson 1: If you push only down, you go only up.
Newtonian Lesson 2:
Corollary A: To go faster, you need more force. The more force you apply, the higher you will rise off the ground.
Corollary B: The higher you are off the ground, the more extended your limbs will be when they strike and leave the ground.
Newtonian Lesson 3: In a relaxed state, with flexibility and sufficient power, you will get full extention, unless you deliberately prevent it by locking your hips in a turned under position, cutting off your stride before completion, or by keeping your foot dorsiflexed at all times- BAD IDEAS!
The concept of restricting movement behind the torso at full speed is a mis-interpretation of a real phenominon. As athletes deliver more force, their hips rise higher over the ground. If the hip is higher the foot will have a smaller contact patch in front and behind the torso (think of a pendulum in this case. This a natural outcome of the additional power required to go faster. Any attempt to alter the natural action of the stride by cutting it off prematurely will result in a dramatic loss of performance
ARM ACTION
The arms CAN control the legs when things are going right but they CAN’T help when mechanics go south (pushing out the back) With good arm action the “pull” is down not back, just as the action is with the legs. A constant angle is seldom maintained with the arms usually moving from around 85degrees in front to about 95 to 100degrees on the back-swing, which is within the acceptable range (arms too close to the torso in front may limit hip rotation and too open in the back may change the center of balance, delay the return, and diminish the elastic response around the shoulder) . It shouldn’t take a lot of arm strength to maintain the proper arm angles or even the rate. The main contribution of upper body strength is to the general strength of the entire organism. The hand comes up to face level in front, and you pull down from there.
The arms will come towards the mid line (but not cross it) with good mechanics, as this initiates the shoulder rotation required to compensate for the counter-rotation of the hip. The mechanics must be checked on two planes- front and side to see what’s really going on.
An incomplete arm action must limit hip rotation by failing to provide sufficient counter-rotation.
The arms can be held at 90 degrees but as speed goes up the forces at work do the opening up without any conscious input. (At a lower velocity, it works as you see with Tommy above, but at the new 100 m velocities, there are greater forces at work) If you deliberately “break” at the elbow, you’ll loose the elastic rebound around the shoulder joint which facilitates the return, and dissipate energy from the upper arm action.
If the angle gets too small in front, it prevents full rotation at the hips by limiting compensatory rotation at the shoulder, moves the CG back slightly, forcing forward movement at the shoulders, interfering with force delivery (extension) through the hip and interfering with the natural rebound/return action of the arm at the shoulder at the completion of the back-swing, and so on and so on…
THE START
You’re strong enough at the start when your drive leg (under load) can extend at the same time as the knee comes forward (no load). If the knee is well forward before the rear leg has much extension, you’re too weak. Triple extension is just a way of describing a position where the body is extended through the hip, knee, and ankle. If you have enough strength for the start, you have enough strength for triple extension, as long as you are relaxed and flexible enough If you concentrate on the arms at the start and forget the legs, the legs will take care of themselves.
1: A mechanically efficient start can be defined by speed through the acceleration period.
2: the efficiency/economy of the start will be reflected, in part, by the athletes ability to finish the race.
Most start problems are correctable, regardless of strength levels, by adjusting the start position to reflect current strength levels rather than to establish one final position and wait for strength to catch up. This is not only possible, but necessary, as the start affects the smooth execution of the whole race. When strength is lacking the COM should be raised as much as possible in the set position by insuring that the arms drop straight down from the shoulders to the line (in both planes), that the hips are as high as possible while still maintaining enough bend at the back leg to ensure force on the back block, and a position close enough to the line that the athlete will automatically raise his COM as fast as is necessary. The start can be re-adjusted in lock-step with strength improvements (the needed changes, while effective, won’t be huge).
Cues for beginner starting
1: hands straight down from shoulders, shoulder width apart- to allow for the highest possible center of gravity for easier transition.
2: front foot just behind “plum line” from the point of the hip to the ground. This is usually accomplished by using a spacing of two foot lengths back from the line for the front foot and one foot length between the front and back block (the average foot is 1/2 the length of the shin)
3: in set the hips should be slightly higher than the shoulders with the back straight.
4: the head should be in line with the back to make the transition during the acceleration phase easier. All the athlete has to worry about is keeping the head in line- not up or down.
Common starting flaws
1: looking up too soon causing the torso to rise and the hips to drop
2: over-striding on the initial steps
3: using a set position that puts the hip behind the front foot
Hip position in the blocks can be individual, but as a rule, a higher hip position allows the majority of athletes to get a better start.
The departure angle at the hip is determined by force available and is not universal. A beginner wouldn’t have remotely enough force to handle a 45 degree angle. 45 degrees is, simply, an easy way to illustrate the effect of distance from the blocks on hip height- (1/1).
The more force you deliver in the blocks the lower the departure angle and the farther ahead of the CG your torso gets, therefore the deeper the knee angles and the more force each subsequent step must deliver to keep from stumbling or even falling. On the edge of control, the knee often wows out to the side, causing unwanted sideways motion.
[Therefore] The deeper the angles during early acceleration, the more likely deflection will occur as power demands on the athlete approach (or even exceed) his capacity. It is also likely that the arm drive will go farther back than necessary, during extreme effort, throwing off balance and rythem (arm action is front biased at the start as maximum effective extension is straight from head to toe and the knee rises much closer to the torso than in the full upright sprint position). The backward and upward arm drive at the start also forces the torso down which can exacerbate any balance or power deficiency problems and make forward arm recovery more difficult. Many times the backward and upward arm action is deliberately exaggerated at the start to keep the torso down.
The emphasis on the lead arm in no way diminishes the action of the backward driving arm. The lead hand emphasis compensates for the mechanical disadvantage the lead hand has in clearing the ground. (The forward lean or pressure, in the set position, however slight, makes clearing the lead hand slower, as it must lift slightly before moving forward while the backward hand is released more easily- this becomes increasingly pronounced as forward lean in the set position increases.)
The key is to set up in a good starting position and concentrate on the lead hand when leaving the blocks. The departure angle is determined by the amount of acceleration as long as your mechanics are correct and relaxed. Make sure that the back controls the head, meaning that there is a straight line from head to hip. If you look up prematurely, thus raising your head you interrupt a smooth transition by forcing the hips to drop, causing the foot to strike ahead of the hip, causing a delay while the body rolls over the foot before force can be applied again. While a longer stride may be desirable, don’t have him reach or push in an effort to achieve it. This will interfere with the natural, cyclic action required for top speed (and probably shorten the total distance covered in the stride as well).
I posted earlier about the need for a gradual rise to the full upright position in starts, which may be more important than more power. I just got some feedback on a guy I worked with on this very matter. He was a quality sprinter (10.23 )but had a big lag at the 10m point. We worked on making sure he didn’t rush to get into the full upright position too early by keeping his head in line with his back at all times (thus allowing his back control his head position at all times). His 60m time dropped .08 in the first race with no other change and the improvement carried over into the 100m as he opened with a 10.13. Obviously, I could site more prominent examples if I hadn’t signed confidentiality agreements, but the principles are the same.
Re Breath
The only time you hold your breath is on the set command (you inhale and hold). When the gun goes off,you exhale slowly under pressure (valsalva). Beyond exhaling under pressure with each breath, the rest is automatic- don’t worry about it. You usually have three breaths in the 100m.
