← Blog

Why does my runner's posture collapse in the final strides of a race?

The fade in the last fifteen metres usually starts in the trunk, not the legs, and it costs more speed than it looks like from the stands.

A runner holds good form through the middle of the race and then, somewhere in the last fifteen or twenty metres, the chest drops, the head tips forward and the arms stop driving. From the stands it reads as simple tiredness. It is more specific than that, and it is worth naming what is actually happening.

What 'collapse' usually is

The muscles that hold the trunk upright, through the core and the hip flexors, tend to fatigue before the legs run out of the ability to push. When they go, the trunk folds forward at the waist. The legs are often still capable of the same stride. What they are no longer getting is an upright frame to push against.

Why it costs more than it looks like

• A forward trunk pulls the hips down and back, which shortens the push off the ground instead of lengthening the stride.
• The arms stop driving front to back and start swinging side to side to help with balance, which does nothing for forward speed.
• A folded chest restricts breathing right at the point in the race when the body needs the most oxygen it can get.

What the Film Room can show

The sprint setting checks trunk lean against a 0 to 20 degree range through the clip. Comparing the reading from the first third of a race to the last third, on the same athlete, on the same run, turns 'they faded' into a number: if the lean is well inside range early and climbing past it late, the fade is visible in the data, not just the finish time.

A single 2D camera can measure the angle changing. It cannot tell you whether the cause is core fatigue, a breathing pattern working against the athlete, or a habit carried over from how they train the last rep of every session. The angle tells you where to look. It does not tell you why.

Related