Temporal dynamics of cortical activity and postural control in response to the first levodopa dose of the day in people with Parkinson's disease.

BACKGROUND: Our understanding of how balance control responds to levodopa over the course of a single day in people with Parkinson's disease (PD) is limited with the majority of studies focused on isolated comparisons of ON vs. OFF levodopa medication. OBJECTIVE: To evaluate the temporal dynamics of postural control following the first levodopa dose of the day during a challenging standing task in a group of people with PD. METHODS: Changes in postural control were evaluated by monitoring cortical activity (covering frontal, motor, parietal and occipital areas), body sway parameters (force platform), and lower limb muscle activity (tibialis anterior and gastrocnemius medialis) in 15 individuals with PD during a semi-tandem standing task. Participants were assessed during two 60 second trials every 30 minutes (ON-30 ON-60 etc.) for 3 hours after the first matinal dose (ON-180). RESULTS: Compared to when tested OFF-medication, cortical activity was increased across all four regions from ON-60 to ON-120 with early increases in alpha and beta band activity observed at ON-30. Levodopa was associated with increased gastrocnemius medialis activity (ON-30 to ON-120) and ankle co-contraction (ON-60 to ON-120). Changes in body sway outcomes (particularly in the anterior-posterior direction) were evident from ON-60 to ON-120. CONCLUSIONS: Our results reveal a 60-minute window within which postural control outcomes may be obtained that are different compared to OFF-state and remain stable (from 60-minutes to 120-minutes after levodopa intake). Identifying a window of opportunity for measurement when individuals are optimally medicated is important for observations in a clinical and research setting.

Kicking Performance in Young U9 to U20 Soccer Players: Assessment of Velocity and Accuracy Simultaneously.

PURPOSE: The purpose of this study was to compare the kicking performance of young soccer players in the U9 to U20 age groups. METHOD: Three hundred and sixty-six Brazilian players were evaluated on an official pitch using three-dimensional kinematics to measure (300 Hz) ball velocity (Vball), foot velocity (Vfoot), Vball/Vfoot ratio, last stride length, and distance between the support foot and the ball. Simultaneously, a two-dimensional procedure was also conducted to compute (60 Hz) the mean radial error, bivariate variable error, and accuracy. Possible age-related differences were assessed through one-way analysis of variance and magnitude-based inferences. RESULTS: Ball velocity increased by 103% (p < .001, η2 = .39) from the U11 age group (48.54 ± 8.31 km/hr) to the U20 age group (98.74 ± 16.35 km/hr). Foot velocity presented a 59% increase (p < .001, η2 = .32) from the U11 age group (49.08 ± 5.16 km/hr) to U20 (78.24 ± 9.49 km/hr). This finding was due to improvement in the quality of foot-ball impact (Vball/Vfoot ratio) from U11 (0.99 ± 0.13 a.u.) to U20 (1.26 ± 0.11 a.u.; p < .001, η2 = .25). Parameters such as mean radial error and accuracy appeared to be impaired during the growth spurt (U13-U15). Last stride length was correlated, low to moderately high, with Vball in all age groups (r = .36-.79). CONCLUSIONS: In summary, we concluded that simple biomechanical parameters of kicking performance presented distinct development. These results suggest that different training strategies specific for each age group could be applied. We provide predictive equations to aid coaches in the long-term monitoring process to develop the kick in soccer or search for talented young players.

Acute Effects of Active, Ballistic, Passive, and Proprioceptive Neuromuscular Facilitation Stretching on Sprint and Vertical Jump Performance in Trained Young Soccer Players.

Oliveira, LP, Vieira, LHP, Aquino, R, Manechini, JPV, Santiago, PRP, and Puggina, EF. Acute effects of active, ballistic, passive, and proprioceptive neuromuscular facilitation stretching on sprint and vertical jump performance in trained young soccer players. J Strength Cond Res 32(8): 2199-2208, 2018-The aim of this study was to compare the acute effects of active (AC), ballistic (BA), passive (PA), and proprioceptive neuromuscular facilitation (PNF) stretching methods on performance in vertical jumping, sit and reach, and sprinting in young soccer players. Twelve trained soccer players (17.67 ± 0.87 years) participated in the study. The jump height (H), peak power (PP), and relative power (RP) in the squat jump (SJ) and countermovement jump (CMJ), the range of motion (ROM), the rating of perceived exertion (RPE), and time (seconds) in 10-20-30-m sprints were evaluated. Significant differences (p < 0.05) in H were found in the comparisons between the PA and control (CO) condition for the SJ. For the CMJ, differences in H were observed between the PA and CO, and PNF with CO and BA, and in the PP between the PNF and CO, AC, and BA, as well as in the RP between the PNF and BA. Significant increases in ROM were found in the AC, BA, PA, and PNF compared with the CO. In relation to RPE, higher scores were reported in the PA and PNF conditions compared with the AC and BA. No significant differences were found in 10-20-30-m sprints. Therefore, the AC and BA methods can be used before vertical jump and sprint activities, with the aim of increasing flexibility. However, the PA and PNF methods should be avoided because of subsequent negative effects on vertical jump performance.

Training Level Does Not Affect Auditory Perception of The Magnitude of Ball Spin in Table Tennis.

Identifying the trajectory and spin of the ball with speed and accuracy is critical for good performance in table tennis. The aim of this study was to analyze the ability of table tennis players presenting different levels of training/experience to identify the magnitude of the ball spin from the sound produced when the racket hit the ball. Four types of "forehand" contact sounds were collected in the laboratory, defined as: Fast Spin (spinning ball forward at 140 r/s); Medium Spin (105 r/s); Slow Spin (84 r/s); and Flat Hit (less than 60 r/s). Thirty-four table tennis players of both sexes (24 men and 10 women) aged 18-40 years listened to the sounds and tried to identify the magnitude of the ball spin. The results revealed that in 50.9% of the cases the table tennis players were able to identify the ball spin and the observed number of correct answers (10.2) was significantly higher (χ2 = 270.4, p <0.05) than the number of correct answers that could occur by chance. On the other hand, the results did not show any relationship between the level of training/experience and auditory perception of the ball spin. This indicates that auditory information contributes to identification of the magnitude of the ball spin, however, it also reveals that, in table tennis, the level of training does not interfere with the auditory perception of the ball spin.

Futsal Match-Related Fatigue Affects Running Performance and Neuromuscular Parameters but Not Finishing Kick Speed or Accuracy.

Purpose: The aim of the present study was to investigate the influence of futsal match-related fatigue on running performance, neuromuscular variables, and finishing kick speed and accuracy. Methods: Ten professional futsal players participated in the study (age: 22.2 ± 2.5 years) and initially performed an incremental protocol to determine maximum oxygen uptake ([Formula: see text]: 50.6 ± 4.9 mL.kg-1.min-1). Next, simulated games were performed, in four periods of 10 min during which heart rate and blood lactate concentration were monitored. The entire games were video recorded for subsequent automatic tracking. Before and immediately after the simulated game, neuromuscular function was measured by maximal isometric force of knee extension, voluntary activation using twitch interpolation technique, and electromyographic activity. Before, at half time, and immediately after the simulated game, the athletes also performed a set of finishing kicks for ball speed and accuracy measurements. Results: Total distance covered (1st half: 1986.6 ± 74.4 m; 2nd half: 1856.0 ± 129.7 m, P = 0.00) and distance covered per minute (1st half: 103.2 ± 4.4 m.min-1; 2nd half: 96.4 ± 7.5 m.min-1, P = 0.00) demonstrated significant declines during the simulated game, as well as maximal isometric force of knee extension (Before: 840.2 ± 66.2 N; After: 751.6 ± 114.3 N, P = 0.04) and voluntary activation (Before: 85.9 ± 7.5%; After: 74.1 ± 12.3%, P = 0.04), however ball speed and accuracy during the finishing kicks were not significantly affected. Conclusion: Therefore, we conclude that despite the decline in running performance and neuromuscular variables presenting an important manifestation of central fatigue, this condition apparently does not affect the speed and accuracy of finishing kicks.