A Study: Same Day Training Hurts Your Gains?

Imagine you’ve got 60 minutes to train 3 times a week. Do you separate your strength and endurance or just stack both into one sweaty session? If the previous (my personal preference) what sort of outcomes can you expect and is there something you should take into consideration.

Plenty of studies have been made to investigate this, yet people argue about it (wich is really nothing surprising). A study from 2003 (Sporer et al.) answered this question, and I've picked it as an example because it answers the question for hybrid athletes quite well. The study was conducted with trained athletes, done with both low intesity and high intesity running and used heavy loads, like in hybrid training. Let's see what it tells us.

The Study

Researchers took a group of trained athletes and put them through a quite intense setup:

Max testing, VO2max testing, cycling intervals, then strength training on repeat. Not once, but nine times to find out if doing cardio before lifting really affects your strength gains.

The cardio was done on a bike. Half the group went all-out with 6x3 minute intervals at nearly max effort. The other half cruised at a steady 70% effort for 36 minutes. After that, everyone hit the weights: leg press and bench press at 75% of their 1RM, reps to failure for four sets. They did this same lifting session either 4, 8, or 24 hours after cardio. The outcome was measured by how many reps they got in total in four sets.

The result?

If the athletes trained legs after doing cardio—especially within 4 or 8 hours—their reps dropped. Significantly. Only after a full day did performance bounce back. But here’s the surprising part: upper body strength was not affected at all. Bench press volume did not suffer, no matter when it was done or was it done after steady state or high intesity. So whether it was HIIT or steady-state, if the athletes hit the same muscle group (in this case, legs), performance dipped.

Total volume of leg press after 4,8 and 24 hours of recovery.

So what does this mean for you? If you’re serious about building strength in the lower body, and you’re also training endurance—timing matters. You can’t expect to hit a squat PR a few hours after hard intervals. At least not consistently.

With upper body however you’ve got a bit more room to play. Conditioning doesn’t seem to interfere as much—at least not in the short term. Therefore if you are short on time, combining loverbody endurance and upperbody strength can be a good option.

Summary: Same day training won’t kill your gains. But if you keep stacking everything on top of each other with no structure, don’t be surprised if your progress stalls. You can have it all—just not all at once.

If you have only 3 days to train per week I would recommend following split for hybrid athletes:

Day 1: Squats + deadlift (alter the movement you do first and more volume between weeks), plyometrics, core.

Day 2: Low / moderate intensity endurance + upper body strength (push + pull)

Day 3: High intensity endurance + accecory movements (shoulder health, lowerbody balance emphasis with sub maximal load & volume)

Check also related posts about the same topic!

Source: Sporer BC, Wenger HA. Effects of aerobic exercise on strength performance following

various periods of recovery. J Strength Cond Res. 2003;17(4):638-644.