Age-dependent Knee Joint Isokinetic Profile in Professional Male Soccer Players

Abstract

Background: The knee-joint isokinetic profile (KJIP) injury risk factor may be modulated by chronological age, however, comparative data for elite male soccer players aged 25 years and older is lacking. Objective: To describe and compare the knee-joint isokinetic profile (KJIP) according to the chronological age of professional male soccer players. Method: In a cross-sectional study design, sixty-three soccer athletes from the first Chilean soccer division (A-series) were divided into younger and older groups (age ≤ 25 years; n = 35 and age 25 years; n = 28, respectively). In both groups the IPKJ was assessed at 60°.s-1 in concentric mode. Results: The older group had lower extensor peak torque (p .05). The younger group showed correlations between flexors peak torque and extensors mean power (p .001). In the older group, flexors peak torque and flexors mean power were correlated. The flexors peak torque, total work, and mean power symmetric index (SI) exhibited values 10 % for both groups. The extensors SI showed values 10 % for mean power, although only in the older group. Conclusion: Several differences in the KJIP were noted between professional male soccer players aged ≤ 25 years and 25 years. Current results offer injury prevention insights, discussed in the current manuscript.

Intra- and inter-limb strength imbalance and asymmetry in soccer: A comparison of elite senior and junior players

“…These results are again consistent with a recent study [43] that confirmed the same relationships by analyzing the same isokinetic strength variables at the same angular velocities and comparing professional soccer players with elite academy players (U-19). The age-related discrepancy in isokinetic muscle strength variables in soccer players may be due to the differences in factors such as players' competition levels, testing period, training load, number of matches played, and strength training regimes [4,44].…”

“…Moreover, the present results reveal that the TW-Q and TW-H variables are higher for seniors than for juniors, meaning that seniors produce more work with quadriceps and hamstrings than juniors. In the context of an isokinetic muscular contraction, total work depicts the muscle's ability to generate strength over the entire range of movement [44]. Over the same joint amplitude, seniors are thus able to produce greater work than juniors with the knee flexor and extensor muscles.…”