Knee Valgus That Returns After a Verbal Cue
A 16-year-old female soccer player is performing a 10-yard sprint-and-cut drill at about 75% of maximal speed. On video, her right knee drifts into valgus during the plant and cut, particularly in the last three of eight repetitions. The coach shouts "knees out" each time; she improves for one repetition, then returns to the same pattern. She reports no knee pain, but her right ankle dorsiflexion is 8 cm on the weight-bearing lunge test versus 11 cm on the left, and right hip external rotation is 30 degrees versus 45 degrees on the left. She has a history of a right ankle sprain two years ago. The team enters playoffs in three weeks, and the coach wants her to "just push through" because she is a starter. She trains four days per week with the team and has one additional strength session.
1. Identify the likely contributors to the valgus pattern and explain why the verbal cue only works briefly.
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The pattern is probably multifactorial. Restricted right ankle dorsiflexion of 8 cm limits how far the knee can translate forward over the foot, so the athlete may compensate by letting the knee drift inward. Reduced right hip external rotation of 30 degrees versus 45 degrees on the left may limit her ability to control femoral rotation during the plant. The prior ankle sprain may have left residual stiffness or altered proprioception. Fatigue is also likely because the valgus appears in the last three of eight repetitions. The cue "knees out" is an external verbal instruction that can temporarily change attention, which explains the one good repetition. It does not create the ankle mobility, hip control, or endurance needed to sustain the position. When the athlete returns to full-speed cutting or becomes fatigued, the underlying constraints reassert themselves. The brief improvement is therefore not evidence that the problem is fixed.
2. What coaching and exercise modifications would you use in the next three weeks? Be specific about cues, constraints, and load.
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I would reduce repeated high-speed cutting volume temporarily and change the task rather than shouting louder. Use a constraint such as a mini-band around the knees during low-level lateral steps, or a target for the knee to track over the second toe during a planned cut. Replace "knees out" with an external focus like "push the ground away" or "reach the cone," and practice at 50-60% speed with video feedback before returning to 75%. Add ankle mobility drills before sessions and hip external rotation strength two to three times per week. Keep strength loads moderate, for example split squats and lateral step-downs at 2-3 sets of 6-8 reps, because the goal is control rather than maximal loading. Cutting drills should be low volume and stopped before the last repetitions become sloppy. The coach's "push through" instruction is not acceptable if mechanics deteriorate with fatigue.
3. What signs would make you regress or hold her from playoff minutes, and how would you communicate that?
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I would hold or regress her if she reports knee pain, develops swelling within 24 hours, or shows the same valgus at speeds above 75% despite the modified drills. I would also regress if her cutting times slow markedly or if she cannot maintain alignment in the final repetitions of a set, because that suggests fatigue-related loss of control. Communication should be specific and shared with the coach: for example, "She can play, but we are capping high-speed cutting repetitions in training and monitoring swelling; if the knee swells or she cannot control the plant, she comes out." I would avoid framing it as a permanent restriction and instead give clear return criteria. Because she is a minor, involve the parent or guardian in any decision that affects playing time. I would not simply tell the coach she is cleared because the valgus has improved for one repetition.