Change-of-direction, speed and jump performance in soccer players: a comparison across different age-categories is a 2019 study that gives very interesting results on these correlations that influence the performances of the soccer player, and published on the Journal of sports sciences.
Below you can read an abstract: "This study examined the age-specific development of vertical jump height, straight and change-of-direction (COD) speed, and COD deficit in one-hundred and eighty-two elite soccer players from different age-categories (U15, U17, U20, and Senior).
All participants were players of two distinct clubs and were undertaking different training routines, as planned by their technical staff members. For this purpose, the soccer players performed: (1) squat and countermovement jumps; (2) a maximal 20-m linear sprint speed test, and (3) the Zigzag COD test.
T he magnitude-based inference approach and standardized differences were used to compare the age-groups. Sprint speed at longer distances (20-m) increased progressively across the age-ranges. In contrast, speed and acceleration performances at shorter distances (5-m) were better in U15 than in the other age-categories.
The COD speed did not change throughout the younger categories but presented a meaningful decrease in the Senior category. Sur prisingly, despite the progressive increase in volume and intensity of neuromuscular training from younger to older categories, the COD deficit presented a gradual increase across the age-groups.
It is possible that simple modulation of the strength-power training program during the maturation process is not sufficient to produce faster adult players with enhanced ability to change direction. Therefore, coaches are strongly encouraged to implement specific COD training practices to tolerate braking at increasing running speeds and appropriate volume and intensity of soccer specific training throughout the players' specialization process."
Volleyball and injuries: what you need to know
Sport injuries in professional volleyball players is an interesting article from 2020, which relates volleyball and the injuries associated with it. Below is an abstract of the article: "Recently there has been a considerable surge in interest in volleyball by both physiotherapists and orthopedic surgeons.
Only few previous studies specified the nature, frequency, and demographics of volleyball injuries. The study was conducted during two league seasons. After the approvals of local bioethics committee and clubs` authorities, contact with the club's doctors was established.
A special survey was designed to standardize the process of acquiring data on a weekly basis. One-hundred-and-ninety-eight women and 301 men were under supervision of the research group. On average, 45% of all players (56% males and 26% females) suffered from injuries and musculoskeletal disorders over two seasons.
Relatively high incidence of injuries during matches was between 17.3 and 33.8 injuries per each 1000 hours of playing. Almost 50% of musculoskeletal problems occurred in the first phase of the season. Over 50% of musculoskeletal problems were reported during trainings.
The blockers are the most affected players in both sex groups. Acute injuries mainly involved knee and ankle joints, while chronic problems affected knee, shoulder, spine and abdominal muscles. Professional volleyball is not a safe sport, especially during a league season.
Attention should be especially paid to ankle, shoulder and knee joints, which are the most commonly injured structures. The study revealed that blockers were the most susceptible to injuries and should be protected by special training regime.
These findings can help to prepare sports medicine personnel and to guide further related research to prevent injuries among volleyball professionals."