The aims of the study are: 1. To examine skeletal muscle and blood metabolites during an official basketball game and to relate those to skeletal muscle performance during and after the game. 2. To investigate whether skeletal muscle and blood metabolites are related to game-induced fatigue. 3. To relate field activity during a basketball game with the responses of skeletal muscle and blood metabolites. 4. To investigate how blood lactate reflects muscle lactate concentration during a basketball game. 5. To determine whether temporary fatigue develops during a basketball game. game.
The basketball players will participate in three experimental games (N = 10/game) on an indoors basketball stadium. During a 2-week familiarization period, volunteers will be familiarized with the experimental procedures and participate in very light training (at local basketball facilities) aimed at developing match tactics and team cohesion. At the end of the familiarization period and before the experimental game, participants will undergo a 3-day baseline performance testing (resting conditions) at University (Department of Physical Education and Sport Sciences, University of Thessaly) facilities. Prior to the games, the players will refrain from strenuous exercise and intake of alcohol for 48 hours and from tobacco and caffeine for 12 h. Dietary intake will be monitored with daily diet recalls for 7 days before the experimental period and will be standardized for all participants by a registered dietitian. The dietitian will also prescribe the meals and snacks on the game-day. On the day of the game, participants will arrive at the stadium 1.5 h before for resting skeletal muscle and blood sampling. For the first muscle biopsy and in preparation for later obtainment of biopsies from vastus lateralis muscle. An incision will be made under local anesthesia (20 mg/ml xylocaine without adrenalin) and covered by sterile band-aid strips and a thigh and shoulder bandages. In addition, an inertial measurement unit (IMU) and a heart rate monitor will be placed on each subject. During the match, a number of physiological measurements will be performed at fixed times (before the game, at half-time and post-match) and after intense exercise periods within the four 10-min periods of the game. Volunteers will be randomly assigned, using the sealed envelope procedure, in six teams representing all field positions and each team will play in one of three experimental games (random allocation using standard procedures) against each other in a full 40-minute game according to official regulations. A total of 10 additional players (from various playing positions) will serve as substitute players that could enter the pitch for a few minutes when a player will have to leave the court (either participate in measurements or will have completed it's pre-determined playing time or in case of an injury). Fifteen players (pre/post game measurement group) will have muscle and blood samples taken at rest, at the end of the 2nd period (half-time) and at the end of the 4th period (end of game). A second group of eight players (intense periods measurement group 1) will have muscle and blood samples collected at rest and during the first and third period of the game (immediately after an intense period of game-play). A third group of seven players (intense periods measurement group 1) will have muscle and blood samples collected at rest and during the second and fourth period of the game (immediately after an intense period of game-play). An intense exercise period of game-play is identified as a period with a heart rate of \> 90% of maximal \[as assessed by the maximal heart rate obtained during a graded exercise test to measure the maximal oxygen consumption (VO2max)\], a high number of high-intensity runs (speed of \> 18 km/h), sprints (speed of \> 25 km/h) and/or jumps evaluated by a professional licensed coach. All muscle biopsies will be sampled from the vastus lateralis. All players will have their field activity and heart rate measured throughout the game using IMU units and heart rate monitors. Games will start at 17.00 - 18 p.m. to avoid diurnal variations and will be held under normal environmental conditions. A standardized 30-min warm-up period will be performed before each game. All games will be videotaped.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
30
Participants will arrive 1.5 hours pre-game for initial vastus lateralis muscle biopsies and blood sampling under local anesthesia (20 mg/ml xylocaine without adrenalin). They will be fitted with IMU sensors and heart rate monitors. Volunteers are randomly assigned to teams(6 teams) for a full 40-minute game. During the match, physiological measurements will be performed at fixed times (pre, at half-time, and post-match) and after intense exercise periods (HR\>90% max, high-speed runs\>18km/h) within the four 10-min periods. Three groups provide samples: Group 1 (n=15): rest, half-time, end-game. Group 2 (n=8): rest, post-intense period in 1st/3rd periods. Group 3 (n=7): rest, post-intense period in 2nd/4th periods. Ten players serve as substitutes. Games will start at 17.00 - 18 p.m. to avoid diurnal variations and will be held under normal environmental conditions. A standardized 30-min warm-up period will be performed before each game.
University of Thessaly, Department of Physical Education and Sports Science
Trikala, Thessaly, Greece
RECRUITINGMeasurement of countermovement jump height
Will be measured using a force platform system
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Bilateral strength peak force and rate of force development on mid-thigh pull
Will be measured using a dynamometer.
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of maximal sprinting speed over 5 meters
5-m sprinting speed will be assessed on the basketball court using infrared photocells
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of maximal sprinting speed over 20 meters
20-m sprinting speed will be assessed on the basketball court using infrared photocells
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of the capacity to perform repeated sprints
5 x 20m repeated maximal sprints will be performed with 25 sec rest in between. Speed will be recorded using infrared photocells
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of field activity variables during the basketball game
Field activity will be continuously recorded during the basketball game using a microsensor inertial measurement unit (Kinexon Perform IMU).
Time frame: Continuous monitoring during each 40-minute game.
Measurement of heart rate during the basketball game ad recording the average and maximal heart rate of the game.
Field activity will be continuously recorded during the basketball game using a Team Polar Pro heart rate monitor.
Time frame: Continuous monitoring during each 40-minute game.
Measurement of skeletal muscle glycogen content
Will be assessed on muscle biopsy samples. Muscle glycogen content will be determined spectrophotometrically.
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of skeletal muscle fiber-type distribution and fiber-type- specific glycogen content.
Will be assessed on muscle biopsy samples by histochemical analysis
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of skeletal muscle phosphocreatine levels
Will be assessed on muscle biopsy samples by a flurometric assay.
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of skeletal muscle lactate
Will be assessed on muscle biopsy samples by a flurometric assay.
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of effort and fatigue
Will be measured by using the Borg Rating of Perceived Exertion (RPE) scale
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Body mass
Body mass will be measured using a beam balance
Time frame: Change from baseline (pre-game) to 40 minutes of the game
Body height
Body height will be measured using a beam balance with a stadiometer
Time frame: At baseline
Body mass index (BMI)
BMI will be calculated using the Quetelet's equation
Time frame: At baseline
Body fat (BF)
Body fat (%) will be assessed by whole-body dual-energy X-ray absorptiometry (DXA)
Time frame: At baseline
Fat mass (FM)
FM (kg) will be assessed by whole-body dual-energy X-ray absorptiometry (DXA)
Time frame: At baseline
Fat-free mass (FFM)
FFM (kg) will be assessed by whole-body dual-energy X-ray absorptiometry (DXA)
Time frame: At baseline
Bone mass density
Bone mass density will be measured by using Dual-emission X-ray absorptiometry
Time frame: At baseline
Bone mass content
Bone mass content will be measured by using Dual-emission X-ray absorptiometry
Time frame: At baseline
Dietary intake
Dietary intake will be assesed over a 7-day period using diet recalls
Time frame: At baseline
Evaluation of physical activity (PA)
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International Physical Activity Questionnaire - IPAQ
Time frame: At baseline
Rest Heart Rate
The rest heart rate will be estimated using a heart rate monitor
Time frame: At baseline
Peak Maximal oxygen consumption (Peak VO2)
Peak VO2 will be estimated by open circuit spirometry via breath by breath method
Time frame: At baseline
Basketball-specific conditioning (endurance)
Yo-Yo intermittent endurance test 1
Time frame: At baseline
Basketball-specific conditioning (recovery)
Yo-Yo intermittent recovery test 1
Time frame: At baseline
Concentric and eccentric isokinetic peak torque of knee extensors and flexors of both dominant and non-dominant limbs
Will be measured at 60°/s using a three-repetition protocol via an isokinetic dynamometer
Time frame: At baseline
Maximal heart rate
Will be measured using an automated online pulmonary gas exchange system via breath- by- breath analysis during a graded exercise testing on a treadmill
Time frame: Change from baseline (pre-game) to that recorded during the 40-minute game
Measurement of blood lactate
Will be measured in capillary blood collected from the index finger using a handheld portable analyzer
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of plasma glucose concentration
Will be measured using a Clinical Chemistry Analyzer and a commercially available kit
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of blood Glycerol concentration
Will be measured using a commercially available kit using a coupled enzyme assay involving glycerol kinase and glycerol phosphate oxidase, resulting in a colorimetric/fluorometric product proportional to the glycerol present.
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of Plasma ammonia concentration
Will be quantitatively determined on an analyzer using a commercially available kit
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of Plasma potassium concentration
Will be measured using a flame photometer (Radiometer FLM3), with lithium as the internal standard
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of Plasma- free fatty acid
Will be measured spectophotometrically using an enzymatic kit
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of blood hemoglobin and hematocrit
Will be measured using an automated hematology analyzer
Time frame: Change from baseline to the: a. 20th minute (half-time) and 40th minute (end of the game) (N=10), b. 5th minute (mid-1st period) and 25th minute (mid-3rd period) (N=10) and c. 15th minute (mid-2nd period) and 35th minute (mid-4th period) (N=10).
Measurement of fluid loss and intake
Will be measured using the measures of body mass (using a digital weight scale) and water consumption during a game.
Time frame: Change from baseline (pre-game) to 40 minutes of the game