Most of us can barely squeeze gym time into our day; so running for an hour outside is probably not happening unless you are training for an upcoming marathon. Believe it or not there is a way to train both your aerobic and anaerobic systems simultaneously in a shorter amount of time; Interval training. During interval training your body can reach near max heart rates, VO2max, high speed, maximal effort, and you get to rest! Talk about efficiency!
Before I get into the science of it, I would like to cite a classic study, the first of its kind.. from 1960.
A study by Christenson EH, et al. called Intermittent and Continuous Running made some great discoveries A subject running at a fast speed, “exhaustive pace” only lasted under 5 minutes at that high speed before ‘verifying’ exhaustion, his VO2 was 5.6, Blood Lactate 150, and he covered .8 miles. The same subject ran at the same speed intermittently. Running for 10 seconds, with 5 seconds of rest the subject was able to last for 30 minutes, (20 minutes of work), he covered 4 miles, VO2 was 5.1, and his blood lactate was only 44.
By taking small breaks we are able to be much more efficient with our exercise. Unlike continuous long duration aerobic exercise, interval exercise doesn’t break down muscle. Interval training spares muscle tissue by allowing your body to replenish its self during rest.
During interval training we can train at a higher level without becoming exhausted. During all out sprints of 10-12 seconds (like in my run cross class) we use an immediate energy system using ATP-PCr for energy. These are intramuscular phosphates that supply energy quickly, but can only last up to about 10 seconds. This system is used at the start of exercise or the point when additional exercise is needed; i.e. a breakaway for a goal in soccer, or the final sprint to the finish line of a 10k race. This system is replenished quickly during rest or steady state aerobic metabolism. The other system that could be used during the 10-12 second of work is the anaerobic Lactic Acid system. This is also a short term energy supplier and it buys time until aerobic glycolysis or rest can take place. This system phosphorylates ADP to ATP, or in other words creates energy from stored muscle glycogen (another reason to eat carbs!!) The aerobic system does produce a small percentage of energy here through glycolysis, especially during the rest period when respiration and heart rate are high.
Interval training can increase anaerobic and aerobic systems. (Short-term and Long-term energy systems) It can allow you to push yourself to your limits, burn more calories, and keep muscle mass.
My Runcross class on Wednesday nights at Equinox South Beach is all sprint intervals! Join me and see how beneficial it is firsthand!
Amelia Sofis M.S, ATC/L, CSCS, PES