I’m bringing up the topic again as it’s a question pretty much every person training will eventually have to decide upon.
A new study was released this month (Oct 2016) in the Journal of Strength & Conditioning Research. Which basically looked at the effects of cardio training performed before resistance training. They tested 4 different realistic cardio protocols.
The 4 treadmill cardio protocols were: *VO2 reserve is not the same as Max Heart Rate (MHR)
60% of VO2R (~70% MHR) reserve for 45 minutes
Think slow jog or very fast walk
75% of the participant's VO2R (~80% MHR) for 20 minutes
Think medium paced jog
90-100% of the participant's VO2R (~90-100% MHR) for intervals of 3 minutes (a 1:1 work to rest ratio) for 5 sets
75% of the participant's VO2R (~80% MHR) at a 6-9% uphill incline for 20 minutes
Think slower jog incline
The resistance training
- High pull
- Bench press
- Push press
Performed for 3 sets of 6–10 repetitions with 70–80% of one repetition-maximum (1RM) with 3-minute rest intervals in between sets.
Average power and velocity were significantly reduced for the high pull, squat, and bench press
Ratings of perceived exertion values for the high pull and squat were significantly higher
Heart rate was significantly higher
Fewer total repetitions performed with squats affected the most
“These results indicate acute RE performance is significantly compromised in healthy men after AE exercise of different type, intensity, and duration with largest reductions observed after high-intensity interval exercise.”
Performing any type of cardio first appears to tap into energy reserves which will negatively affect resistance training performed after. The magnitude of this effect will no doubt be dependent on the individuals fitness levels and nutrient timing around workouts.
To repeat, when performing longer sessions including both weights and cardio, the stress placed on the body is greater and your peri-nutrition becomes even more important.
In any case this study does help support the previous suggestion to either perform your priority (weight training in most cases) first or ideally perform the sessions at separate times.