Cardio is often avoided by powerlifters and even bodybuilders at times for fear that it will diminish results in strength and hypertrophy. The concern is based on a phenomena called the interference effect that occurs when pairing strength training and endurance training together. This pairing is thought to impede directed adaptation and down regulate adaptive signalling for strength and hypertrophy (1). On the surface it seem pretty clear cut, avoid cardio or you risk losing out on potential results. But there are several considerations to take into account before we can make legitimate recommendations on this.
Not all cardiovascular training is the same. There is a big difference between doing HIIT (high intensity interval training) and doing LISS (low intensity steady state). What is the frequency and duration of the cardio? Is it occurring before training, after training or on alternate days? Even where you are in your contest or meet prep is an important factor to consider. Beyond that, the modality you select may also play a role in your ability to recover. For example stair climbing may be more fatiguing than walking on a treadmill with an incline.
To make the best decision we need to be clear on our objective when implementing cardio. In most cases it’s for one or more of the following reasons:
To decrease body fat
To increase wok capacity
To improve health (more often an issue in super-heavyweight powerlifters)
Aerobic fitness is an undervalued aspect of strength training. Primarily because if your level of fitness is so low that you can’t recover for subsequent sets your performance will be stifled. Improving your aerobic capacity can enhance recovery through increased aerobic response, improved lactate removal and enhanced phosphocreatine regeneration (2). Although this is a positive adaptation, once your recovery reaches a reasonable level there is no additional benefit to improvements in aerobic fitness (3).
This is in fact this is the cut off whereby the cost benefit of cardiovascular training becomes imbalanced. The interference effect may come into play and you end up wasting resources on improving aerobic fitness rather than investing that same energy into strength training or hypertrophy. Fatigue will also accumulate potentially decreasing performance in subsequent training bouts (4).
Because bodybuilders typically train with high volumes aerobic fitness doesn’t seem to be an issue for them. So the incorporation of cardio is primarily to improve fat loss. Depending on where you are at in your prep various forms of cardio may become inappropriate. For instance HIIT cardio during your peak may have a muscle sparing effect and decrease the likelihood of interference but the amount of fatigue generated would likely offset the benefits.
A 2019 paper titled Recommendations For Natural Bodybuilding Contest Preparation: Resistance And Cardiovascular Training found “Interference with strength training adaptations increases concomitantly with frequency and duration of cardiovascular training. Thus, the lowest frequency and duration possible while achieving sufficient fat loss should be used. Full--body modalities or cycling may reduce interference. High intensities may as well; however, require more recovery. Fasted cardiovascular training may not have benefits over fed--state and could be detrimental.” (4).
To summarize, aerobic training can have a positive impact on work capacity and recovery in powerlifters without any measurable amount of detriment to performance. However, once aerobic fitness improves beyond a certain point there is no additional benefit and may negatively impact performance through increased fatigue and the interference effect (3). Bodybuilders can use cardiovascular training as an effective method to reduce body fat. Negative impacts on strength and hypertrophy can occur with higher frequency, durations and intensities due to increased fatigue and the interference effect. Starting with a conservative frequency, duration and intensity and progressing slowly as needed is likely the best way to mitigate these potential consequences.
1. Wilson, Jacob M., Pedro J. Marin, Matthew R. Rhea, Stephanie M.c. Wilson, Jeremy P. Loenneke, and Jody C. Anderson. "Concurrent Training." Journal of Strength and Conditioning Research 26, no. 8 (2012): 2293-307. doi:10.1519/jsc.0b013e31823a3e2d.
2. Tomlin, Dona L., and Howard A. Wenger. "The Relationship Between Aerobic Fitness and Recovery from High Intensity Intermittent Exercise." Sports Medicine 31, no. 1 (2001): 1-11. doi:10.2165/00007256-200131010-00001.
3. Hoffman, Jay R. "The Relationship between Aerobic Fitness and Recovery from High-Intensity Exercise in Infantry Soldiers." Military Medicine 162, no. 7 (1997): 484-88. doi:10.1093/milmed/162.7.484.
4. Helms, Eric R., Alan A. Aragon, and Peter J. Fitschen. "Evidence-based Recommendations for Natural Bodybuilding Contest Preparation: Nutrition and Supplementation." Journal of the International Society of Sports Nutrition 11, no. 1 (2014). doi:10.1186/1550-2783-11-20.