Posted by: PFB
Q: I read an article on one rep max testing. I feel I need to use a single joint movement to find my true 1RM for a particular muscle to negate secondary muscle involvement, i.e. dumbbell fly as opposed to a dumbbell press. Even though some single joint movements involve secondary muscles, anterior delts for flyes or posterior delts for pullovers, the stress appears to be greater for the targeted muscle than would an exercise such as a dumbbell press where the stronger muscles, mostly triceps, tend to take over the exercise. My question is is it advisable to use single joint movements to test large muscles' 1RM?
A: Some authorities feel that you can and should test 1RM's on just about any exercise including single-joint movements; whereas, others feel that by using the big, compound, multi-joint movements (i.e bench press & squat as pushing movements, chin-ups and deadlifts as pulling movements) will suffice in determining your fiber makeup and how to appropriately train those muscles. Then, of course, there are others that believe that 1RM testing is unnecessary and potentially dangerous (although no research has ever reported injury data from 1RM testing) and that perhaps lower intensities should be used - several regression formulas exist to extrapolate one rep max. Keep in mind that for the most part, submaximal tests appear valid for predicting 1RM (Hoeger et al., 1987, however, showed great variability between the leg press and leg curl when comparing maximum number of reps at 60% 1RM) but the accuracy is greater when 10 reps or less are performed. Some drawbacks to 1RM testing include: apprehension of lifting may compromise performance, it is time consuming and difficult to standardize, and if untrained, it may take several sessions of strength testing to obtain consistent measures (the older you are, the more sessions required.) Furthermore, many clinicians are reluctant to perform 1RM testing in patients because of potential muscle soreness/injury and adverse responses in deconditioned subjects. However, Barnard et al., 1999 showed that with proper technique, 1RM testing may be performed even in cardiac rehabilitation patients without injury or significant muscle soreness.
Now, with all that said, the answer to your question is yes and no! Plenty of research using isokinetic testing of knee flexion/extension exists with suggestions of ideal quad:ham strength ratios (see Colliander & Tesch, 1989 for example), and although the validity of such testing is questionable to begin with, I would definitely refrain from performing a 1RM isotonic (or more appropriately auxotonic) test of knee extension. The shear forces in this movement are far too high - you're just asking for trouble. (Yes, it would be safer to test the joint initially from an extended position and some researchers even use a shortened ROM to decrease the injury potential, but why chance it?) I would also advise against testing 1RMs in flyes or pullovers due to the long lever arm. The risk far outweighs any benefit in those movements - use the formulas mentioned above instead.