The Study: Association of Age With Muscle Size and Strength Before and After Short-Term Resistance Training in Young Adults .           

The Facts:

a. The subjects were 826 adult males and females aged 18-39.

b. They participated in a 12 week program of strength training of only the non-dominate arm.

c. “Isometric (maximal voluntary contraction [MVC]) and dynamic strength (1 repetition maximum [1RM]) of the elbow flexors and cross-sectional area (CSA) of the biceps-brachii using magnetic resonance imaging (MRI) scans were measured before and after training.” 

d. The subjects trained two times a week.

e. Using dumbbells, they performed three sets of the following exercises: biceps preacher curl, overhead triceps extension, biceps concentration curl, triceps kickback, and standing biceps curl.”

f. At the beginning of the study, the one repetition strength of the subjects was determined and a formula was used to estimate the amount of weight that the subjects would be able to lift for 12, 8 and 6 repetitions.

g. On weeks 1-4 the exercises were performed for three sets for the weight calculated for the 12 repetitions, on weeks 5-8 it was three sets with the weight calculated for the 8 repetitions and on weeks 9-12 it was three sets with the weight calculated for the 6 repetitions. There was a two minute rest period between each set.

h. If the subject was able to lift two more repetitions on the third set of the exercise using he calculated weight then the weight was increased for the next session for that exercise.

i. After 12 weeks the authors found that isometric maximal voluntary contraction and the dynamic strength 1 rep maximum of the elbow flexors and cross-sectional area of the biceps-brachii all increased.

j. Interestingly they found an association of age to the pre study measurements with the younger subjects showing higher results. But by the end of the study they found, “ In the entire cohort, age was related to change in 1RM but not in muscle size or MVC (Table 2). A sex-specific pattern of adaptation to this protocol has previously been reported (12). We therefore also analyzed these data according to sex, but the relationship with age was not different to that of the entire cohort.”

k. “After controlling for baseline values, improvements in 1RM in the second decade were greater than the improvements in both the third and forth decades. In turn, greater improvements were seen in the third decade than the forth.”, but the effect was small.

l. They concluded that “…age does not affect the response to training in a meaningful way through early adulthood.”  

Take Home:

Resistance training improved all the variables measured in this study. The younger subjects did show more improvement in the 1RM but the authors concluded that age did not have a meaningful effect on the training response in these subjects. 

Reviewer's Comments:

I know that this is an interesting study in that it tends to confirm what most of us might think in that resistance training improved muscle strength and size. But there is something more. Although the ages here are relatively young, the results were close between the younger and older subjects. This is important considering our aging population. The authors referenced another study, “Ivey et al. (13), who showed that the change in muscle volume, measured by MRI, with 9 weeks of dynamic strength training was not different in younger (20–29 yr of age) compared with older (65–75 yr of age) men.” This may mean that getting old and weak may be changed to getting older but being able to perform the activities of daily living for a long time if you make the effort. For those who are closer to hell than high school (Coleman’s Fables) this is important!

Reviewer:  Roger Coleman DC

Editor: Mark R. Payne DC

Reference: Joshua Lowndes, Richard L Carpenter, Robert F Zoeller et.al. Association of Age With Muscle Size and Strength Before and After Short-Term Resistance Training in Young Adults . J Strength Cond Res. 2009Oct;23(7): 191520.doi: 10.1519/JSC. 0b013e3181b94b35.

Link to Abstract: https://pubmed.ncbi.nlm.nih.gov/19749605/

Link to Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4103410/pdf/nihms601407.pdf