Why does my sprinter's knee lift look good in drills and disappear in the blocks?
A high knee in an A-skip and a high knee in the first two steps out of the blocks are asking two different amounts of the same muscle.
A knee-lift drill looks clean on its own: good height, good position, done at a pace the athlete can control. Then the gun goes and the same knee lift is nowhere in the first two steps out of the blocks. That is not the athlete forgetting the pattern. It is the pattern being asked for at a completely different speed and load.
Why a drill can look right and still not transfer
A drill gives the hip flexor time to reach the position, unloaded or lightly loaded, at a pace the athlete sets. The blocks ask for the same range of motion produced fast, against full body weight, while also driving out horizontally, in a fraction of the time a walking or skipping drill allows. A position that is available slowly is not automatically available fast. That gap is strength and speed, not memory.
What to check before assuming the athlete is not trying
- Whether the knee lift is missing on every step out of the blocks, or fades in after the first two, which points at drive-phase strength rather than a forgotten cue.
- Whether the same athlete's knee lift holds up on a standing start at a similar speed, which would point at the blocks specifically rather than at speed in general.
- Whether the block spacing is forcing a first step too long or too short for the athlete to clear it and still lift the knee.
What the block-start setting actually reports
The Film Room's block-start setting reads drive-phase trunk lean and whether the athlete stands up early, whether the hips climb instead of driving out, and back-leg extension at clearance, across the first six steps. It is built to read the drive phase, not a stationary drill, so a skip drill and a block start do not compare cleanly against the same numbers. Film the drill on its own and judge it by eye, then compare block starts only against other block starts.
A camera reading knee angle from the side can say whether the position was reached. It cannot say whether the hip flexor is strong enough to reach that position at speed against resistance, and that strength question is one a video can point toward but never answer on its own.
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Related
Why your sprinter's back leg never fully extends out of the blocks
The rear leg is supposed to finish straight at clearance, and when it does not, the fix is almost never in the leg itself.
Read →Why your sprinter's first step out of the blocks goes nowhere
A short, flat first step usually means the front leg never got the chance to push, not that the athlete is slow off the gun.
Read →How far forward should a sprinter lean?
A lot out of the blocks, very little at top speed, and never by bending at the waist, which is the version that gets taught by accident.
Read →Try it: Sprint timer app: 40-yard dash and flying sprints with one phone