Guide
Skip leg day. Do single-leg day.
A squat trains two legs pushing together on stable ground. A run is 160+ single-leg landings per minute, each one a small balance emergency. If you only have two or three strength slots a week, single-leg work buys you more than the barbell does.
What single-leg training fixes that squats can't
Pelvic control. On one leg, your glute medius has to hold your pelvis level. In a two-leg squat it barely works. A dropping pelvis is behind a lot of runners' knee and IT band pain.
Left-right gaps. Almost everyone has a stronger leg. Two-leg lifts let the strong side quietly take over; single-leg lifts expose and close the gap before it becomes an overuse injury on the weak side.
Balance under fatigue. Late in a race your form doesn't fail because your muscles are weak — it fails because your stabilizers are cooked. Single-leg training trains exactly those.
The five worth doing
1 · Rear-foot-elevated split squat. The king. Big strength stimulus, built-in balance demand, and a hip-flexor stretch for the trailing leg. Bodyweight first; add dumbbells when 10 clean reps feel easy.
2 · Single-leg Romanian deadlift. Hamstrings and glutes as brakes and balancers. Keep the hips square and the reach slow — wobbling is part of the training effect, not a failure.
3 · Step-up. Hill running in exercise form. Whole foot on the box, drive through the heel, control the descent. The eccentric lowering is half the value.
4 · Single-leg calf raise. The calf-Achilles unit handles more load than any other tissue in running. A useful benchmark: 20+ smooth single-leg raises per side. Most runners test far below it.
5 · Side plank. Technically zero legs — but it trains the same lateral chain that keeps you stacked over one foot, and it has some of the best evidence among core exercises for runners.
How to fit them into a running week
Two sessions a week is enough for most runners: one on a non-running day, one as a 20-minute add-on after an easy run. Keep hard things apart — heavy single-leg work the day before intervals guarantees a bad workout twice. And progress load slowly: add reps first, then weight, never both at once.
Get a week built around your schedule
Our free builder places single-leg strength sessions around your actual running days — intervals and long runs protected — and picks exercises for your equipment and pain history.
Next read: Knee pain from running: the strength work that actually helps
General information, not medical advice. Train within pain-free range and get persistent issues assessed by a professional.