Science for practice

Age-Related Changes in Muscular Strength and Speed-Strength Qualities

L. S. Dvorkin, Cand. Sc. (Biology), Sverdlovsk; A. S. Medvedev, Cand. Sc. (Pedagogy), State Central Institute of Physical Culture (GTsOLIFK)

English summary of Tyazhelaya Atletika. Ezhegodnik 1983 (Moscow: Fizkultura i Sport, 1983), pp. 31–37: the text is paraphrased, not translated; data tables are given in full with English labels.

Context

• Strength grows fastest at puberty (Tambieva, Chernik 1962; Ilyin 1965). Per kg of bodyweight, 13–14-year-olds already equal adults; relative strength is formed by 16–17 and holds to 41–50 (Korobkov, 1958). Drivers: muscle mass, motor-unit recruitment, motor-visceral reflexes (Mogendovich, 1965).
• Speed-strength grows fastest at 11–14 and peaks at 17–18 (Filin, 1974; Giris; Poko; Belbergova). Absolute strength drives speed (Verkhoshansky, 1970), and speed-strength predicts success in lifting (Myulberg; Ippolitov; Dvorkin).
• Long-term data on lifters from age 12–14 were lacking.

Design

From 1967 to 1979 Dvorkin tested grip and back (deadlift) dynamometry and the standing long jump. The subjects were 1100 lifters aged 12–22, 856 middle-distance runners (youth sports schools, Urals Polytechnic Institute), 669 untrained schoolboys aged 12–16 and 1324 untrained students.

Results

• At 12: grip — untrained 28.2, lifters 26.7, runners 26.2 kg. Back — lifters 78.4, untrained 70.8, runners 68.2 kg. Jump — runners 175, untrained 169.3, lifters 164 cm. The lifters were strongest but slowest.
• 12–16: lifters' grip doubled (53.2 kg, +99.2%; runners +69.8%, untrained +63.4%). Back rose 78.2% (139.7 kg; 65.8% and 52.8%). The jump rose 45.5% (238.7 cm; 24.7% and 17.9%). Speed-strength grew 56–62% less than strength, so it is harder to improve. Runners doubled their grip only by 18, the untrained by 20. Against the 16-year-old lifters, runners caught up in back strength at 17 (relative gain) and 19 (absolute), the untrained at 21 and 22; in the jump runners caught up at 18 (absolute) and 21 (relative), and the untrained never did.
• 17–20: grip gains nearly halved (lifters 45.0%, runners 40.8%, untrained 35.1%). Back gains fell 21% overall (untrained 52.8→17.5%, runners 65.8→54.4%), but lifters rose 7% thanks to a surge at 17. Jump gains fell 40% (17.8, 20.1, 15%).
• 21–22: small gains. Back: untrained 25.6, lifters 23.5, runners 12.8%. Jump: 1.2, 1.6, 3.9% (lifters, runners, untrained). Grip: lifters 16.8, runners 0.8, untrained 0.4%.
• Overall: mean gains of 57.5% at 12–16, 36.6% at 17–20 and 9.6% at 21–22. Lifters changed most, runners less, the untrained least. (The text gives 29.5% for the jump at 12–16; Table 1 gives 29.4.)

Table 1. Mean rates of gain, all groups, %

Table 2. Relative change from age 12 to 22, %

Interpretation and advice

• Speed-strength: lifters have nearly exhausted their room to improve, runners have a little left and the untrained a lot. Lifters began 6% behind runners despite being stronger, and overtook them only at 15. Lifters should add middle-distance (and sprint) running from 12–14; runners should add strength work.
• Grip: it is a weak link for lifters. It stops improving naturally at about 20, and after 22 lifters gain at most 2 kg a year. Their lead came at puberty (6.6 kg a year vs 4.5 kg); at 17–20 the groups gained similar amounts (3.0, 2.7 and 2.5 kg). Current methods do little for it. Use rope climbing, hanging on wall bars, bar and rings, and kettlebell juggling. Do the first sets with a plain grip, then a hook grip, then straps. Also do plain-grip barbell rows, standing and prone on a bench.
• Back strength: runners and the untrained can still improve it a lot, especially with weights, and probably also the large leg muscles.

Table 3. Standing long jump by age

WL — weightlifters, R — middle-distance runners, NA — untrained peers (applies to Tables 3–5).

Table 4. Grip (hand and forearm) strength by age

Several of the weightlifters' printed values (coefficients of variation, annual gains at 14 and 15) do not agree exactly with the means and σ; reproduced as printed.

Table 5. Back (deadlift) strength by age

* Probably damaged in the source. The weightlifters' age-12 mean is printed as 73.4, but the article text gives 78.4 ± 13.2 kg, and the annual gain (18.9) and percentages in the following rows are consistent with 78.4. Their age-13 coefficient of variation is printed as 1.5, but σ/mean gives 11.5.

Conclusions

• Systematic sport gives more harmonious, higher development without changing its biological laws (Antropova; Groshenkov, Voznyak; Motylyanskaya et al.; Filin).
• Weightlifting from age 12 clearly beats running or no sport for both strength and speed-strength.
• Lifters, especially beginners, should add middle-distance running and train grip strength more intensively.