THE BALL KICKING SPEED: A NEW, EFFICIENT PERFORMANCE INDICATOR IN YOUTH SOCCER
This study evaluated the maximum kicking speed, with instep kick and side-foot kick, with both legs, of 119 soccer players, distributed in age groups (U-15, U-17 and U-19) and, within them in 1st team and reserves. After a 15-minute warm-up, doing kicks with instep kick and side-foot kick, increasing intensity slowly, players performed 3 maximum shots with each leg and with each technique (12 shots in total) with 11 meters of running. The best shot was selected for the analysis. The maximum kick speed was greater in 1st team players (vs reserves). Differences were higher in U-15 and U-17 compared to those found in U-19. The kicking speed in football could be a tool for evaluating success in young players.
TAKE HOME MESSAGES
- Successful players (1st team) show higher ball kicking speeds than less successful ones (reserves).
- These differences are higher in U-15 and U-17.
- Within them, the differences in both shots are higher in the dominant leg, compared to the non-dominant one.
- The maximum kick speed increases with age.
- Differences in ball kicking speed with dominant and non-dominant leg decrease with age.
- The ball kicking speed (and the differences between the dominant and non-dominant leg) could be useful as a tool to evaluate the success of the players.
HAMSTRING RATE OF TORQUE DEVELOPMENT IS MORE AFFECTED THAN MAXIMAL VOLUNTARY CONTRACTION AFTER A PROFESSIONAL SOCCER MATCH
This study evaluated the effect of match-induced fatigue on knee muscle strength and strength-ratio parameters after a single professional match. A group of Brazilian male professional soccer players were tested before and after a soccer match for knee flexors (hamstring) and extensors (quadriceps) isometric peak torque (MVC) and rate of torque development (RTD) as well as hamstring-to-quadriceps ratio (H:Q), at 30º of knee flexion.
TAKE HOME MESSAGES
- Reductions in hamstring RTD0-50, RTD0-200, and RTD0-50 H:Q occurred immediately after a soccer match, whilst quadriceps RTD0-50 was increased.
- No changes in hamstring and quadriceps MVC occurred after the match.
- No correlations were observed between total minutes played and changes in RTD H:Q, indicating that the level of neuromuscular fatigue after match may be affected by factors such as physical status, field position, and specific tactical demands, developing different intensities which are not necessarily related to the total amount of time played.
Match-induced fatigue impaired the ability to rapidly produce force at an angle (30º of knee flexion) were injuries are most susceptible to occur (which is common in sprinting, pivoting, side-cutting, and jumping).
MUSCLE OXYGENATION INDUCED BY CYCLING EXERCISE DOES NOT ACCELERATE RECOVERY KINETICS FOLLOWING EXERCISE-INDUCED MUSCLE DAMAGE IN HUMANS: A RANDOMIZED CROSS-OVER STUDY
Abaïdia, A.-E., Cosyns, S., & Dupont, G. (2019). Muscle oxygenation induced by cycling exercise does not accelerate recovery kinetics following exercise-induced muscle damage in humans: a randomized cross-over study. Respiratory Physiology & Neurobiology.
10 soccer players performed 75 eccentric contractions of a knee flexors exercise, and then the day after, did an intermittent cycling exercise of 12 minutes (15s work - 15s rest at intensity between 11 (light) and 13 (somewhat hard) on the Borg’s RPE scale) or recovered passively, in a cross-over experimental design with both legs. Oxygenation during cycling was assessed using Near Infrared Spectroscopy, and isokinetic and isometric strength, countermovement jumps, muscle soreness, perceived recovery and CK concentrations were assessed through a 72h period (see Figure)
TAKE HOME MESSAGES
- Intermittent cycling at light - somewhat hard intensity one day after the exercise, did increase knee flexors oxygenation, but had a small detrimental effect on eccentric strength, muscle soreness and perceived recovery, with no effect on the other recovery measures.
The oxygenation of the muscle that is achieved by practicing intermittent cycling at low intensity on the first day of recovery after muscle-damaging exercise (ie a football game) does not seem to improve or accelerate muscle recovery