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In Defence of High Rep Workouts (Aug 23, 2009 answer on Bodybuilding.com)

Traditional Bodybuilding dogma tells us that you need to stay within a certain rep range to build muscle. But everyone has a genetic ceiling in terms of “strength”.

Muscle Fiber Recruitment also plays a key role in this discussion because skeletal muscle actions involve selective recruitment of muscle fiber types. Depending on the activity the Nervous System(NS) preferentially recruits ST muscle fibers 1st, then FTa & lastly FTb fiber types(1). There is also a minimum threshold of stimulation needed to elicit the use of a Motor Unit (ie: nerve and all the muscle fibers it stimulates). It is an all or none response (just like a light switch) It is either on or off, no in between.

 Characteristics of ST fibers(2):

  • Velocity of nerve conduction is slow
  •  Utilizes myosin ATPase which also acts slowly
  •  Motor unit force is low
  •  Aerobic Capacity is High
  •  Anaerobic capacity is Low


Characteristics of FT Fibers(2):


FTa: (Type 2a)

  • Velocity of nerve conduction is Fast
  •  utilizes myosin ATPase which acts very quickly
  •  Motor Unit force is High
  •  Aerobic Capacity is Moderate
  •  Anaerobic Capacity is High.


FTb: (Type 2b)

  • Velocity of nerve conduction is Fast
  •  Utilizes Myosin ATPase which acts very quickly
  •  Motor unit force is High
  •  Aerobic Capacity is Low
  • Anaerobic Capacity is High.


FTb muscle fibers have the greatest potential for growth, but are the hardest to recruit. With traditional bodybuilding dogma most trainees will probably never even tap into those High Threshold Motor Units(HTMU)(aka: FTb fibers) for the simple fact that the trainees are under the impression that you have to stay within the 6-12 or 8-15 rep ranges(just examples) & move the weight in a deliberate , controlled manner.

What are ways to recruit the HTMU?
1) Lift with more Intensity(ie: heavier loads.) This usually leads to slower speed of movement. The heavier the load the slower the tempo of the lift becomes, independant of intent.  

Here is an example of an Off Season Upper Body Strength workout I used with one of my bodybuilding clients.


Workout A : Monday

Sets & Reps(rest period in seconds)

A) Push Press

5 x 5,3,3,1,1( 3-0-X) 120-180

B) Bench Press

5 x 5,3,3,1,1( 3-0-X) 120-180

C) Weighted Chin Up

3 x 5,3,3( 3-0-X) 120-180

D) Weighted Dips

3 x 5,3,3( 3-0-X) 120-180

E1) Leaning 1 Arm DB Lateral Raise

2 x 12(1-1-1) 10

E2) Reverse Pec Dec(Thumbs down Grip)

2 x 20( 1-2-1) 60



2) Increase the speed of the lift/movement. Here is where the Power equation( P = Force x Velocity) comes into the picture. IMO Power movements are very under utilized in the bodybuilding arena. The faster you move a load(velocity) the more Motor Units you will need to recruit. Then when the Intensity(load) is increased your NS will need to recruit the HTMU(the one’s with the most growth potential) to help produce enough force to move the load at a faster speed. Now, remember with the FTb & FTa muscle Fibers the velocity of nerve conduction is very fast (also remember that it is an all or none response). Therefore to move a load at a faster speed the body has no choice but to recruit the “Big Boys ” to the party.


There are certain lifts that inherently have to be done Explosively or you would never be able to perform them otherwise. They include all Olympic lifts & there variations. Plus, you could also perform the Concentric (lifting/raising portion) Phase of some of the more common lifts explosively. Exercises like Bench Press, Squats, Dips, Leg Press, etc… Now, you would have to decrease the intensity (load) because the speed of a lift is inversely proportional to the intensity (load). (ie: the heavier you lift the slower you move the load). Would I advise or prescribe high rep work for Olympic style lifts? Never. They are too technical. But, I would prescribe it for body weight or lower intensity exercises like squats or bench press.


When training with high reps at a high velocity one should remember that “they should stop when they become incapable of performing a rep dynamically” (3)


3)Increase the number of reps: Selective Recruitment means that if you are doing very high reps (50-100), like the Original Poster (OP) asked, that the NS will utilize the Low Threshold Motor Units (ST fibers) first. Then the FTa fibers, Then when they (FTa) fatigue or the Intensity is too high the NS will recruit the FTb fibers. This is also a way to recruit the “Big Boys”


Legendary Strength coach Charles Poliquin says; “It is my experience that there are specific repetition ranges that are more appropriate for certain muscle functions. “  He also states that: “ For example training the knee flexors (aka: hamstrings) with sets of 12 reps appears to have little bearing on hypertrophy gains. Conversely, when training the knee extensors (Quads) sets up to 50 reps can induce hypertrophy. The reason appears to be that the flexors are used for mainly explosive tasks, while the knee extensors are used in maintaining posture against gravity and for repeated stretch-shortening tasks such as rowing.” (4)


Taking the above information into account training the Hamstrings with high reps would not be optimal for bodybuilding purposes. But, 2 x 50 or 1 x 100 for Quads would be quite beneficial.

NOTE: The higher the reps the less sets you need to perform.


Here is an example of a “Hundreds Workout” as written in the Encyclopedia of Muscle & Strength  by Jim Stoppani PhD :


Table 6.1 (page 83)                             Workout 1


Muscle Group





Bench Press




Incline DB Fly




Cable Cross-over




Wide Grip Pull-down




Seated Cable Row




Straight Arm Pull-down




Smith Machine Shoulder Press




Dumbbell Lateral Raise




Dumbbell Shrug




Cable Crunch




The point I am trying make is not to discount high rep work. If you lift/move at a higher rate of speed , increase intensity(load) Or both( increased speed & intensity) OR increase the # of reps you can recruit HTMU.

I am not suggesting that this take the place of time proven practices. Just to keep an open mind & think “Out of the Box”. High rep work can do wonders for many people in many different situations. Used intermittently of course!


  1. Periodization Training for Sports/Bompa & Carrera 2nd Edition; Ch 2, Page 17
  2. Physiology of Sport & Exercise/ Willmore & Costill 2nd Edition; Table 1.2, Page 42
  3. Periodization Training for Sports/Bompa & Carrera 2nd Edition; Page 206
  4. Modern Trends in Strength Training: Vol. 1/Poliquin 2nd Edition; Page 13

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