The aim of this study is to investigate the effects of photobiomodulation therapy (PBMT) on recovery after high-intensity, intermittent exercises in female futsal athletes. It is hypothesized that PBMT is superior to placebo condition in improving the recovery of muscle function after high-intensity, intermittent exercises.
The aim of this project is to investigate the effects of photobiomodulation therapy (PBMT) on recovery of muscle function after high-intensity, intermittent exercises in female futsal athletes. A crossover experimental studies will be conducted with 15 female futsal athletes. Participants will undergo two consecutive blocks (B1 and B2) involving the Bangsbo sprint test (BST) and the yoyo intermittent recovery level-1 (YYIR1) at two time points (M1 and M2), separated by a 2-week washout period. PBMT will be applied in the 10-minute interval between blocks B1 and B2. PBMT will be applied according to the randomization order at M1 and M2, so that the participant who receives active PBMT at M1 will receive placebo PBMT at M2, and vice versa. The following variables will be analyzed in the BST: (1) Best Time: the shortest time obtained in the sprints, (2) Total Time (TT): the sum of the time of all sprints, and (4) Fatigue Index (FI): the difference between the worst and best times. For the yo-yo test, the total distance covered will be analyzed as an indicator of aerobic performance. In addition, the rating of perceived exertion (RPE) will be measured immediately after each test in blocks B1 and B2.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
15
Participants will receive the active Photobiomodulation
Participants will receive the placebo Photobiomodulation
Physical performance in the Bangsbo Sprint Test
The ability to perform repeated sprints with changes of direction will be assessed using the Bangsbo sprint test (BST). The test consists of seven sprints of 34.2 meters between the starting cone (A) and the finishing cone (E), interspersed with a 25-second active recovery period. During recovery, participants perform a light jog back to the starting point (cone A). The change of direction (right or left) between cones B and C in the first sprint is determined by each participant's individual preference, and subsequent sprints are performed alternately between the right and left sides. Participants will be verbally encouraged to perform their best in all sprints. The following variables were analyzed: total time (sum of all sprints), and fatigue index (FI) = 100 - (average time/best time) x 100). The BST is considered valid and reliable for analyzing aerobic recovery capacity.
Time frame: Baseline (M1) and after 2 weeks (M2)
Performance in Yoyo intermittent recovery level 1
Aerobic recovery capacity in high-intensity intermittent running will be assessed using the yo-yo intermittent recovery test level 1 (YYIR1). The protocol consists of 40-meter runs (stages) between cones B and C (20 m out + 20 m back) followed by 10 seconds of active recovery between cones A and B (walking a 5 m path). The initial speed of the test is 10 km/h, with a progressive increase in speed by auditory stimulus (beeps) (the time between "beeps" decreases at each stage, forcing the athlete to run faster). The test is terminated when the participant does not reach the marking line (cone B) within the stipulated time in two attempts (even if not consecutive) or is unable to continue the test due to fatigue/exhaustion (6). Participants are verbally encouraged to perform as well as possible during the test. The total distance covered (in meters) will be used as a variable for aerobic performance. The YYIR1 test is considered valid and reliable for analyzing aerobic recovery capacity.
Time frame: Baseline (M1) and after 2 weeks (M2)
Rating of perceived exertion (RPE)
The RPE will be recorded immediately after the Bangsbo and YYIR1 tests, using the Borg 6-20 scale. The scale contains 15 points ranging from 6 "no effort" to 20 "maximum effort", and the participant indicate a number on the scale that represent their perceived exertion at that moment. RPE is a simple, valid and reliable instrument for assessing perceived exertion in running tests. All participants will be previously familiarized with the scale through the cognitive anchoring procedure.
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Time frame: Baseline (M1) and after 2 weeks (M2)