What Science Says About Doing Cardio Post-Leg Day

Scrolling through FitTok, you’ve likely stumbled upon the debate: Should you do cardio after leg day? Opinions range from claiming it’s a fat-burning, recovery-boosting miracle to warning that it sabotages your muscle gains. The reality? Cardio after leg day is generally safe and can even be beneficial, depending on your fitness goals. However, there are a few nuances to consider.

Can You Do Cardio After Leg Day?

Yes, you absolutely can. Post-leg day cardio won’t "kill your gains" or disrupt your progress, says Dan Churchill, MS, trainer and performance chef with Centr.

In fact, your muscles are already warmed up, making it a safe time to include light to moderate-intensity cardio. “Avoid intense sessions like sprints or heavy cycling after a grueling leg workout to reduce injury risks,” Churchill advises.

What About Muscle Gains?

The concern about cardio interfering with strength gains stems from its potential effect on the mTOR signaling pathway key for muscle growth. However, research, such as a 2022 review published in Sports Medicine, shows that combining strength and cardio in the same session does not significantly compromise muscle hypertrophy or strength development.

The exception? Explosive strength gains (important for activities like sprinting or powerlifting) may be slightly affected.

Benefits of Doing Cardio After Leg Day

• Cardiovascular Health: Aerobic exercise improves heart health, boosts endurance, and reduces chronic disease risks.

• Active Recovery: Gentle post-leg day cardio can help circulate waste products from exercise and ease into recovery.

• Convenience: If you know soreness will keep you from cardio in the days after, doing it right after strength training might be a smart strategy.

Myths About Cardio After Strength Training

A common belief is that post-leg day cardio helps reduce delayed-onset muscle soreness (DOMS). However, there’s no solid evidence to support this claim. According to exercise physiologist Luke Carlson, MS, cardio neither improves nor worsens recovery after an intense strength workout.

Potential Risks of Post-Leg Day Cardio

While cardio is safe after leg day, keep these risks in mind:

• Injury Risk: Fatigued muscles may struggle with high-intensity cardio, increasing the chance of strain or missteps. Stick to low- to moderate-intensity activities.

• Compromised Cardio Performance: If you’re training for an endurance event, prioritize cardio first or on separate days to optimize performance.

• Overtraining: Advanced athletes may benefit from incorporating cardio post-strength to simulate race conditions, but beginners should rest in between sessions to avoid overdoing it.

Best Types of Cardio After Leg Day

The key is keeping intensity low to moderate:

• Walking or incline walking

• Easy cycling

• Elliptical

• Gentle stair climbing

Aim for a perceived effort level of 6 or lower on a 10-point scale. Use the "talk test" to gauge intensity if you can talk but not sing, you’re in the moderate zone.

Recovery Tips After Leg Day

Cardio alone won’t aid muscle recovery, but incorporating these tips can help:

• Protein: Consume 1.2 to 2 grams per kilogram of body weight daily.

• Sleep: Aim for at least 8 hours a night to repair and rebuild muscle tissue.

• Massage or Foam Rolling: These methods can help reduce DOMS and perceived fatigue.

• Active Recovery: Engage in light activities like walking or yoga.

• Contrast Therapy or Compression Boots: These can improve circulation and reduce inflammation.

The Bottom Line

Doing cardio after leg day won’t derail your progress and can be part of a well-rounded fitness routine. Just keep it light or moderate, and listen to your body. If your primary goal is strength or endurance, tailor your schedule accordingly to maximize performance and recovery.

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