Concurrent Training

Concurrent Training
By Greg Nuckols
Cardiovascular training has been much maligned in the powerlifting community. By that, I am referring to purely aerobic work. You’ll find people touting the benefits of sled work, sprints, or barbell complexes, but steady state aerobic work? Never! We’ve been told it’ll make us small and weak so many times we’ve taken the bait. The real story is a little more nuanced than that. Let’s dive in.
Mode-specific
In a 2012 meta-analysis1 it was found that combining strength training and aerobic training did in fact decrease the rate of progress both in terms of strength and hypertrophy. However, when different modes of exercise were compared in isolation (i.e. running and lifting by themselves or cycling and lifting by themselves) the negative effects only materialized when combining lifting and running. That’s right, cycling didn’t cause any decrements in strength and hypertrophy. There are two likely explanations:

a) Joint angles – cycling includes joint angles more similar to squatting. Instead of minimal hip and knee flexion you get with jogging, the joint range of motion trained for cycling is much more relevant to weight room activities.

b) Muscle damage. With running, you have to absorb the shock of each step, and this eccentric loading can cause muscle damage. With cycling on the other hand, all the muscle action is concentric, which causes minimal muscle damage. Thus, it doesn’t add to the total amount of recovery work your body has to do between strength training sessions. In fact, it might aid in recovery by substantially increasing blood flow to the legs without causing further damage.

Additional hypertrophy with cycling?
Some studies have actually shown that combining cycling and strength training can cause greater hypertrophy than strength training alone. Admittedly, these studies incorporate lower training volumes than the average RTS reader will be using, but mechanistically they show that cycling, rather than detracting from the strength and hypertrophy response to training, may actually be additive in terms of overall anabolic stimulus. What’s more, the studies were conducted with cycling and strength training both taking place within the same training day2 and also on separate days3. This tells us that there’s little need to fear an interference effect with both acute and chronic effects of combining cycling and lifting.

Over time, as your aerobic capacity improves, sets that used to take 3 minutes for full recovery may only take 2 minutes, and a level of volume that used to run you into the ground will become much more manageable.

A small caution: it’s important to note that the studies do find a decreased rate of force production when combining cycling and lifting. It therefore may be prudent to taper aerobic work along with strength training leading up to a meet. However, this isn’t a major concern for a powerlifter. Total time under tension for a max lift will almost always be shorter than time it takes the body to produce maximum force utilizing stored ATP and phosphocreatine as rapid energy substrates. Whether you reach max force in .25 second or .5 seconds shouldn’t be a major concern in a lift that can take 4-5 seconds or longer.
Energy expenditure
Lifting heavy stuff is an energy-intensive endeavor. In 1994, research found that oxygen consumption could be predicted, and thus derive caloric expenditure, with a pretty high degree of accuracy based on total work done in the deadlift4. The equation they found is:

Oxygen consumption (L) = 2.63 + 0.80 x work (in kilojoules)

Then, multiply oxygen consumption by 4.9 to get caloric expenditure since each liter of oxygen consumed means about 4.9 kcals burned.
So, just to do a little rough math – let’s say you’re a 235kg deadlifter, hitting 85% for 5 sets of 3. Your range of motion is about half a meter.

Oxygen consumption = 2.63 + 0.80 x (200kg x 0.5m x 9.8m/s^2 / 1000) x 15 total reps

For that set, you will consume about 14.4 L of oxygen, and expend 70 kcals. That’s about how many calories you’d burn running half a mile if you’re around 200 pounds.
Although this study was looking specifically at the deadlift, the same principles would likely hold true for squats. At the very least, there is no reason to believe they wouldn’t.
Here are some implications. If you feel just fine to work out after jogging half a mile, dedicated aerobic work may not be necessary for you. However, if you’re out of shape aerobically, you’ll take longer to produce the energy necessary for recovery between sets, and consequently your training volume will suffer. You’ll probably benefit from adding some dedicated aerobic work to your training. Another important thing to point out is that as you get stronger your aerobic endurance should also improve. Since caloric expenditure is based on total work, you increase it by putting more weight on the bar (which will happen as you get stronger), and by doing more volume (which will become necessary to keep progressing past a certain point).
Why do aerobic work when lifting can also be aerobically taxing?
Risk versus reward. The more aerobically fatigued you are, the more likely you are to slip up and hurt yourself lifting heavy stuff. Use aerobic work to improve aerobic capacity, and use strength work to get strong. Over time, as your aerobic capacity improves, sets that used to take 3 minutes for full recovery may only take 2 minutes, and a level of volume that used to run you into the ground will become much more manageable.
Conclusion
Aerobic work won’t make you small and weak, especially if you stick to cycling. What’s more, a solid aerobic base can help you safely push yourself harder in the gym and increase training density and volume. If you value your performance, maintaining a strong base of aerobic fitness will help you, not hurt you.

About the Author Greg is a strength coach, writer, and elite drug-free powerlifter. His passion is synthesizing scientific research and in-the-trenches experience to stay at the forefront of the strength game, and to become the best coach and athlete possible. With best lifts including a 755 squat, 475 bench press, and 725 deadlift, he knows what it takes to get you strong. Visit www.gregnuckols.com for more of his work.

References
1 http://www.ncbi.nlm.nih.gov/pubmed/22002517
2 http://www.ncbi.nlm.nih.gov/pubmed/24408998
3 http://www.ncbi.nlm.nih.gov/pubmed/22706947
4 http://www.ncbi.nlm.nih.gov/pubmed/7932947