What Is Concurrent Training?

The goal is to be both strong and aerobically fit. However, combining high-volume endurance work with strength training can create an interference effect. Too much endurance can blunt strength gains if not programmed correctly. This is not a reason to avoid doing both — it is a reason to be smart about how you structure your training week.

Concurrent training is relevant far beyond competitive athletes. If you want to run a decent 5km and still have visible muscle definition, you are training concurrently. If you play a sport that demands both strength and stamina — rugby, football, MMA, Hyrox — concurrent training is non-negotiable. The challenge is balancing the two qualities so they complement each other rather than interfere.

The Interference Effect

The interference effect is real but manageable. Research shows 2 to 3 strength sessions and 2 to 3 endurance sessions per week can coexist if volume is controlled. The key is separating hard sessions by 6 to 8 hours or alternating days.

A common mistake is doing hard endurance and hard strength in the same session. One athlete did back-to-back sessions and saw his strength plateau. After spacing them out, he improved his squat by 10kg in three months. The science behind this is straightforward: endurance training activates AMPK pathways that promote aerobic adaptation, while strength training activates mTOR pathways that promote muscle growth. When both are stimulated at the same time, they can compete — but only at high volumes. Moderate amounts of both can coexist without issue.

The practical rule of thumb is simple: if a session is going to leave you genuinely exhausted, give it breathing room. A hard interval run in the morning and a heavy squat session in the evening is fine if you have had time to eat and recover. Doing both back-to-back with no break is where you start to see diminishing returns.

Practical Scheduling

Plan your week with dedicated days for each quality. Use shorter, intense workouts instead of long, grinding sessions. For Hyrox athletes, this means balancing running with strength work for the stations.

A well-structured concurrent training week might look like this: Monday is a strength session focused on lower body compound movements. Tuesday is a tempo run or interval session. Wednesday is an upper body strength day. Thursday is an easy recovery run. Friday is a full-body strength session. Saturday is a long run or a Hyrox-specific session combining running and station work. Sunday is a rest day. This approach ensures each quality gets adequate attention without the sessions stepping on each other.

The biggest mistake recreational athletes make is doing too much volume at moderate intensity. Long, slow runs combined with high-rep gym sessions add up to a lot of fatigue without producing great results in either area. Shorter, more focused sessions — 45 to 60 minutes — with clear intent for each one will get you better results in less time.

Common Mistakes to Avoid

• Running and lifting heavy in the same session without adequate recovery time between them.
• Ignoring nutrition: concurrent training increases your caloric and protein needs. Under-eating will stall both strength and endurance gains.
• Skip training days without a plan. Random workouts produce random results. Write your sessions down and follow a structure.
• Neglecting sleep. Concurrent training demands more recovery than single-discipline training. Seven to nine hours per night is the minimum.