Weight lifting (Resistance exercise) and aerobic endurance training don’t mix!
First let’s define “Resistance Exercise” and “Aerobic Endurance Training”. Let me ask – what pictures came into your mind when you read those quoted words? You probably have the right idea.
Resistance Exercise is essentially your classic weight lifting. Bench Press. Squats. Deadlifts. Arm Curls. Lat Pulldowns. You get the idea. These exercises are also considered “Anaerobic” – meaning without oxygen. We won’t get too sciency here but due to the very short time period we typically do these exercises, we utilize an energy system in the body that does not utilized oxygen to release energy, the Creatine Phosphate System (ok I got a little sciency).
Now, what about Aerobic Endurance Training? If you pictured someone going out for a jog – you are correct! Endurance exercises are typically done over a long period of time, slowly. So jogging for 30 minutes. Biking for an hour. That marathon you did last month. These are “Aerobic” or “Endurance” exercises or training events. What about sprinting? If you thought this was an endurance exercise – wrong! Sprint work, running, or High Intensity Interval Training is considered Anaerobic.
But why do the above not mix? Why is Anaerobic (Resistance Exercise) training impaired by Aerobic (Endurance) exercise?
When you combine them strength and performance is impaired. (2,7,8). Callister et al showed (5) that concurrent sprint (type II fiber training) alongside aerobic endurance training (type I fiber training) decreased sprint speed and jump power! Explanations from the authors state possible adverse neural changes/alterations of muscle proteins in the fibers.
Endurance training does not present enough of a stimulus for hypertrophy of type I muscle fibers. Type I fibers actually resist hypertrophy by downregulating their own testosterone receptors. From the Kraemer study, the National Strength and Conditioning Association states:
“Hypertrophy does not typically take place with aerobic endurance training. In fact, oxidative stress may actually promote a decrease in muscle fiber size in order to optimize oxygen transport into the cell.” (1)
“The aerobic endurance training group had a higher cortisol response and a reduced testosterone response, promoting a more catabolic environment in the body, even for muscle proteins. The resistance training group saw increases in testosterone but decreases in cortisol in response to the exercise stress, indicating a greater anabolic environment.” (1)
So all in all, when you concurrently do endurance exercise training with resistance/weight lifting you get:
And talking about needing increased cardiovascular fitness..
“It appears that every athlete needs a basic level of cardiovascular endurance, which can be achieved using a wide variety of training modalities and programs. The traditional modality has been the slow, long-distance run. For the strength and power athlete, however, this may be irrelevant or even detrimental to power development. Adequate gains in aerobic fitness can be accomplished with interval training when appropriate and needed. The old concept of an ‘aerobic base’ for purposes of recovery in anaerobic sports is somewhat misunderstood; athletes can gain aerobic training adaptations without the use of long-distance running because a variety of alternative training programs exist.” (1)
So if you are looking to build pounds of muscle mass and skyrocket your strength – skip the jog!