Date: Wed, 12 Mar 1997
From: "Charles I. Staley" 
Subject: 20-rep deadlifts

With respect to the person who injured his back during the 18th rep on a
set of deadlifts:

Although there is a faction that promotes 20 rep deadlifts and/or
squats, I think this practice should be carefully evaluated. Of course,
one can acquire an injury doing almost anything, (and for almost any
number of reps), nevertheless:

1) With 20 repetitions, you would place the involved musculature under
tension for quite a while, depending on the tempo used. With a 5 second
tempo, we'd be looking at 100 seconds. My colleague Charles Poliquin
suggests that the ideal time under tension for hypertrophy is between 40
and 70 seconds; for maximal strength it is preferrably less than 20
seconds. A brief consideration of energy pathways shows that such a
prolonged set has a significant aerobic component. Using these
parameters, 20 rep deadlifts would be appropriate for muscular
endurance, or (possibly) hypertrophy for lifters who are mostly Type I
fiber. For Type II stimulation however, much higher tensions are
required.

2) Movements requiring large contribution of stabilizing and
neutralizing muscles (such as squatting, deadlifting, cleans, snatches,
etc.) may be best employed using short durations--as fatigue sets in, it
becomes increasingly difficult to maintain optimal spinal position, knee
tracking, head position, etc. Additionally, fatigue may cause breathing
technique to deteriorate, which compromises spinal stabilization as
well.

I think a lot of lifters have mis-identified their objectives -- fatigue
is the by-product of training, not the goal! I was consulting to a
football player once who wanted to improve his bench press. During a
phase where we were performing 10 sets of 3 reps, this athlete
constantly complained that he never felt exhausted, or nauseated, never
had a pump, etc. However, we raised his bench press by 40 pounds in 16
weeks! So the moral is, "What is the objective?"

If you are determined to use high repetition sets, you may be better off
using machines, or at least exercises which don't place the spine in
such jeopardy. Identify your training objective, then find the most
safe and effective ways to achieve those objectives.

Charles I. Staley, B.Sc., MSS
International Sports Sciences Association
Phone: (800) 892-ISSA; E-mail: staley@west.net
Please visit "Fundamentals of Strength Training for Sport":
www.west.net/~staley/welcome.html