This cardio move is great for runners; it not only works the lower fibres of the abs, but it helps train for quick turnover in gait to increase speed.
- Run in place while lifting your knees high to the level of your waist. Engage your abs as the knee comes up.
- Pump your arms to warm up your upper body.
- Keep running with high knees for 30 seconds.
Image Source: POPSUGAR Photography / Kyle Hartman