Hypertrophy-Specific Training Q & A (February 2002)

From the Hypertrophy-Specific Training Series

Rep Cadence (tempo) and HST

Q: Hi, I am going to be starting my first cycle of HST and am wondering if there is a rep cadence [tempo] that works best with HST?

A: Actually there is. Basically, during the 15's the reps should start out slow and then speed up as you feel the burn begin to kill your strength. After all, the whole point is to flush the muscle with lactic acid.

During the 10's you should go slower when the weight is light. That way it will still be difficult to complete the set. As the weight gets heavier simply increase the tempo to ensure that you complete the set. BE careful not to get too sloppy though. It will do little good to use momentum to move the weight during the 10s.

The first week of 5's should be slow on the way down but still pretty explosive on the way up. Then as the weight nears your 5 rep max you will have no real control over how fast you move the weight. It will generally go slow simply because it is so heavy.

During negatives you should lower the weight in about 2 - 2.5 seconds. This may seem too quick to most traditionalists. Research has shown that if you go too slow during negatives you don't get the same growth stimulus. it begins to resemble the effect of isometrics if you go too slow. This is one reason why the old principle of "time under tension" isn't so simple as just time. The action of the muscle while under load is very important when trying to produce a specific effect.

How does microtrauma actually happen?

Q: Bryan, you say that one of the main principles of HST is “strain-induced” muscle cell damage. Doesn’t strain come from stretching something beyond its normal limits? How could muscle cells be “strained” when they never are really stretched. Doesn’t a muscle contraction actually shorten a muscle fiber? It doesn’t make sense.

A: You are right when you say that the range of motion of a joint will not allow most muscles to passively stretch far enough to cause stretch/strain microtrauma on muscle cells. However, an actively contracting muscle creates a different environment

Sarcomeres (area of a muscle fiber measured from Z line to Z-line) are hooked together in series at their Z lines. Each individual sarcomere “fatigues” at different rates when they are contracting. When one sarcomere fatigues the others continue to contract (or even go into rigor) and pull on it from each end leading to strain induced disruptions in the phospholipid membrane. These disruptions are actually important because IGF-1 and other growth factors, acting in a paracrine manner, travel to adjacent cells and help with repair, satellite cell activation, and hypertrophy. So growth factors actually ooze out from the cell when the sarcolema gets disrupted (microtrauma).

You could also think of it this way. Get 3 rubber bands, 2 strong ones and 1 weak one. Hook them together with the weak one in the middle, then pull from each end to simulate contraction under load. All the rubber bands will stretch, but the weak one will stretch the most.

Now, this is where Time under Tension comes into play. Once again, think of the rubber bands as sarcomeres. Lets say the weak rubber band starts out strong but "fails" or begins to over-stretch early, even though at first it appears to be just as strong as the other two. Let’s also say that the rubber bands have to stretch a certain distance before the signal for hypertrophy is achieved.

If you quickly pull on the rubber bands with high force, all the bands will stretch sufficiently to achieve the signal for hypertrophy. Of course if you maintain this high force the rubber bands will first fail (fatigue), then stretch (strain) then break (become necrotic and be replaced with fibrous tissue). So if you are going to use high force you have to control the time under tension or you will cause too much damage.

On the other hand, lets say you pull on all the rubber bands with less force. With less force none of the rubber bands will reach a stretch required for hypertrophy at first. However, as you hold the stretch, the weak one begins to fail (fatigue) and then it starts to get stretched as the other stronger rubber bands pull back to their original length. The weak rubber band then achieves the necessary stretch (strain) for hypertrophy but the others don’t.  This is why people have noticed that a certain amount of time under load is required for growth.

So with high loads more fibers reach the required stretch/strain to induce growth in less time. With lighter loads it takes more time under load but it will eventually lead to growth. The absolute size achieved will depend on the absolute load the fibers are exposed to so reach high loads will eventually become necessary to achieve significant hypertrophy.

 Best way to eat for HST

Q: How am I supposed to eat when using HST? I’ve read a lot about diets but I was just wondering if you had any advice.

A: This is a very good question. In reality, nutrition should be optimized for the desired goal, then left alone regardless of the training regimen.

HST principles optimize the training stimulus. Now, if you go on a fat loss diet and eat too few calories, HST will prevent as much muscle loss as possible because it is optimized for muscle growth. If you are trying to gain weight, HST is still optimized for muscle growth, so HST will ensure the greatest possible gains with a mass building diet.

Here is the only thing I would recommend as far as adjusting the diet. The purpose of the 15's and early 10's is to flush the tissue with lactic acid and create and accumulation of oxidative by products in the cells. In order to optimize this you must be eating a fair amount of carbs. When you eat a lot of carbs the muscle will burn a lot of glycogen, creating lactic acid and producing the desired effect (enhanced tendon strength and functional oxidative capacity).

When you get into the heavy 5's and negatives the carbs should come down a bit. Insulin sensitivity declines as muscle damage increases. I would say about 30% carbs during the really heavy weeks is sufficient to support growth.

About the Author

Bryan Haycock M.Sc. is an exercise physiologist and NPC judge. Bryan has been bodybuilding for over 20 years and holds certifications with the NSCA, ACE, and is a member of the American College of Sports Medicine. Bryan is currently the Editor in Chief of ThinkMuscle.com and is the founder and CEO of LifeStyleMgmt.com. Bryan is a highly sought after authority on the physiology of muscle growth and fat loss. Bryan also specializes in the management of type-II diabetes through diet and exercise.