Must Owen learn to run again?

Q: Back in 2003 England footballer Michael Owen was told that he may have to learn to run all over again because his posture was plaguing him with hamstring injuries. Biomechanical experts discovered that Owen, instead of running at pace on his toes like top sprinters, was putting too much pressure on his heels. This is why he has always suffered hamstring problems and risks further injuries to his calves and Achilles tendons. As a steady distance runner, I’ve always tried to avoid injury by following the maxim ‘heel into toes’. Please explain the mechanics of foot strike, and whether a footballer, who goes through the whole range of walking, jogging, and sprinting in a game, has to be very conscious of the position of his foot in each of those actions.

Ken Naylor

A: First, there is no way of knowing for certain that Owen’s hamstring problems are the result of putting too much pressure on his heels. No carefully controlled scientific study has ever linked heel striking in general, or increased force directed through the heel in particular, with an increased risk of hamstring or calf problems. Most hamstring injuries in athletes who run probably occur because the hamstrings are not strong enough to withstand the forces placed on them during running. The key stresses, of course, are the eccentric ones – when the hamstrings are exerting force while simultaneously being stretched. During running, this occurs primarily during the swing phase of the gait cycle, as the leg swings forward just prior to foot contact with the ground. During swing, the hamstrings are active because they are trying to control the speed and magnitude of swing, but they are also being stretched because, after all, the leg does move forwards. Instead of re-learning how to run, Owen would probably be better off strengthening his hamstrings in a running-specific way. There are many exercises which can accomplish this, but one of the best is the drill described below. This exercise, which is often called ‘bicycle leg swings with and without resistance’, is great for rehabilitating hurt hamstrings and preventing hamstring trouble in general.

To carry out bicycle leg swings, follow these instructions:

• Stand with your weight fully supported on your left leg (you may place your right hand on a wall or other support to maintain balance);
• Begin by flexing your right hip and raising your right knee up to waist height, so that your right thigh is parallel with the ground and your right knee flexed to 90° or more;
• Now swing the lower part of your right leg forwards until your knee is nearly fully extended and your thigh still parallel to the ground;
• As your right knee nears full extension, allow your right thigh to drop down and back until your leg is extended behind your body (as if following through on a running stride). Your right knee should be near full extension until it reaches the peak of the backswing;
• As you approach the end of the backswing, bend your right knee so that your heel moves closely towards your buttocks;
• Then move your right knee forwards until it returns to the appropriate position in front of your body, with your thigh parallel to the ground.

Repeat this entire sequence of actions in a smooth manner, so that the hip and leg move though a continuous arc without stopping or pausing. Once you are able to coordinate the movement, strive to perform the swings at a cadence of at least 12 every 10 seconds. Carry out 50-60 swings with each leg. Rest for a few moments then repeat, performing the overall routine about four times per week.

Once you are really good at this exercise, you should add resistance in the form of an elastic cord. Attach the cord at about knee height to a completely stable and strong post or other structure about three feet in front of you; attach the other end of the cord to the ankle of the leg which is about to swing, then perform the exercise in the normal way. The elastic should be taut enough to accelerate your leg movement as it swings forwards (thus putting increased pressure on the hamstrings) and resist backswing. As your strength improves, you may progress to cords which provide greater resistance. If you carry out the swings regularly, your resistance to hamstring troubles will be greatly increased.

With regard to the mechanics of foot strike, bear in mind that during running most athletes first hit the ground with the outside border of the shoe – some with the rear lateral part of the shoe (the rearfoot strikers) and most others with the middle lateral region of the shoe (the midfoot strikers). A large number of endurance runners are rearfoot (‘heel’) strikers, but many others are actually midfoot strikers. (However, it may be interesting for you to know that even forefoot strikers usually let the heel hit the ground at some point during foot strike.) Football players tend to make initial contact more towards the front of the foot, and this may help improve their speed; a couple of studies have shown that forefoot strikers have slightly shorter ground-contact times than rearfoot strikers, an effect which could improve stride rate. However, there is no evidence that forefoot striking decreases the risk of hamstring or calf injury.

In fact, force-plate studies have revealed that the maximal vertical ground-reaction force during running is typically about three times body weight – for both rearfoot and midfoot strikers; in other words, hitting the ground with the midfoot doesn’t reduce or cushion this impact force. There are, however, some subtle differences in what is called the centre of pressure (COP) – the geometric centre of the distribution of force applied by the foot to the ground. In rearfoot strikers, the COP moves from the rear lateral border of the foot to the midline within about 15 milliseconds of initial contact, then continues along the midline to the centre of the forefoot, where it remains for most of the stance phase of gait. By contrast, midfoot strikers have an initial COP at about 50% of shoe length, which then moves backwards until the rear part of the shoe makes contact with the ground. After moving to the back of the foot, the COP then zips forward to the middle of the forefoot (to approximately the same place as for rearfoot running) and stays there until toe-off.

These are interesting differences, but does a rearfoot COP foretell hamstring woes? Doubtful! To understand hamstring injury during running, it is critically important to look at the toughest stresses which are placed on the ‘strings’ – the eccentric ones related to their swings.

Owen Anderson