All about acceleration
by John Shepherd Jumps Coach.
John is a former international athlete who now coaches a group including a former EU Junior Champion, UK age group best record holders and various internationals.
In the video below, John talks all things acceleration:
Technical aspects of how to develop acceleration
Using equipment such as sledges and harness belts
Read on to see the notes from the video:
Acceleration is obviously needed for sprinters, but also for other track and field athletes. The more powerful you are at moving your body from 0-10 metres with added resistance from a sled or harness, the greater your ability to express speed and power. A long jumper who is good at acceleration will invariably have a better top end speed. A shot putter who can move a sled very quickly over 10 metres will potentially be able to put further than an athlete who doesn’t have that accelerative capacity.
There are two potential benefits from developing your acceleration:
It will improve your acceleration and get you to top speed at a more optimum level
It is a bit like weight training: a means to develop specific strength in a way which improves your athletic event performance. g. squat exercises will improve your running, jumping and throwing, as long as they are done in a way which is compatible with the rest of your training. This is also true of acceleration power training.
How to develop acceleration?
Hills, sleds and harnesses are all means to develop acceleration if used appropriately.
Some elements to watch out for:
Consider the gradient and/or resistance at which you train
If you run up a too-steep hill, or try to tow a sled with a very heavy weight you will affect your running/sprinting mechanics. If the resistance is too great, you will accelerate in a way which has less specific transferability to your actual sprinting.
- Harnesses: it is tempting for the athlete behind to pull too hard. They must enable the athlete who is running to develop their acceleration without being yanked backwards. They must be able to get into good accelerative positions: posture, torso position and leg drive.
- Sled: 20-30% of the athlete’s body weight on the sled is optimal. You should be able to move the sled relatively quickly, but crucially with the right sprint mechanics.
What are sprint mechanics?
- Torso position: When you leave the blocks, the torso angle is around 45°, so when starting an accelerative run with a sled, the athlete should be in a suitable forward-leaning position and should maintain an angled torso as they move the sled forward. This applies to all acceleration, whether uphill, with resistance or on the flat.
- Torso to leg relation: The angle of the torso must follow through into the legs to avoid a folded-over position. You are looking for the torso and legs to be in alignment, particularly in the first 3-4 steps. This enables the athlete to push through the spine and work the ground behind them. If the body position is ‘broken’ and the athlete is bending forward from the hips but not getting the legs in the right position, they will not optimally accelerate.
- Arms: We have all seen sprinters leaving the blocks with a very long arm position and the body at a 45° The arm drive sets up the leg drive, so it is crucial that the athlete swings the arms long over the first couple of steps to enable the legs to work into the track surface. I will often cue three long arm actions before the arms bend at the elbows whilst accelerating. It is the forward leg’s arm that the athlete swings up first. So if the athlete is in an accelerative position with the right leg to the front, then move the right arm up quickly as they accelerate. This will enable the right leg to extend fully and push the athlete forwards.
- Leg movement: Athletes push against the track surface to create momentum when accelerating, driving through the hip. This should be emphasised when sled towing. If you take your foot too quickly off the track surface, you will not impart sufficient force to optimise acceleration. Sports science indicates that the best accelerative athletes are those who can get the greatest cadence with the greatest amount of force being imparted back into the track surface. Getting acceleration right is a combination of cadence (speed) and power (force), which is one of the reasons that overloading a sled can be detrimental.
Heel position: After the first 3-4 steps of acceleration with a sled, or coming out of the blocks, the mechanics of acceleration slightly change. The ‘heel recovery’ (the way the heel lifts behind the body) has to start to come up. Always maintain a low heel position through the accelerative phase. If you lift the heel up too quickly, two things happen. First, you will start to ‘cycle’ rather than drive forwards and second you will take too much air time on each step. Keeping the heel close to the track surface enables a lot of power to be put into the track surface and the right direction achieved.
A lot of contemporary sprint coaches talk about moving the feet away from you during acceleration. Moving the foot forwards quickly gets the drive into the track surface as if you were pushing against the surface. By taking the feet away from you whilst accelerating, you achieve more effective acceleration. I would recommend experimenting with both methods
Having said that, when you are in the blocks, you do push back against the blocks, but after that once you have cleared the blocks, and athlete can also think about moving their feet away from them, keeping their heels low to the ground.
How far do you run with resistance?
How far should you tow a sled or have an athlete restrained or pulled back by another athlete? This is a difficult question, as age, event, time in training year and accelerative capacity all determine the length of acceleration for advanced athletes. In general terms for club athletes, 10-15 metres is optimum. Beyond about 15 metres, the athlete will be coming closer to their upright sprinting position.
What acceleration training aids are available?
There are a few variations of resistance training aids, including harnesses which can be held by a fellow athlete, sleds which can be loaded with weights and pulled using a waist harness and even parachutes. All of these are designed to provide resistance, as discussed in this video and blog.
There are also cadence harnesses, which are used to pull the athlete forwards, for overspeed training (also achieved by running down hill). There is a lot of debate over the effectiveness of cadence training and it is certainly true that cadence devices should be used with specific training goals in mind to avoid compromising biomechanics.