The purpose of this randomized crossover study was to compare the acute effects of repeated-sprint protocols incorporating different numbers of 180-degree changes of direction in adolescent female basketball players. Twenty participants completed three exercise conditions in a randomized, counterbalanced order: 10 × 15-m linear sprints, 10 × 15-m sprints incorporating one 180-degree change of direction, and 10 × 15-m sprints incorporating two 180-degree changes of direction. Each sprint was followed by 30 seconds of passive recovery. Sprint performance, perceived exertion, heart rate, peripheral oxygen saturation, and systolic and diastolic blood pressure were assessed. The study examined whether increasing the number of changes of direction affected repeated-sprint performance and acute perceptual and cardiovascular responses.
This was an acute, randomized, counterbalanced, three-condition crossover study in which each participant completed all experimental conditions and served as her own control. Following a standardized warm-up, participants completed one of three repeated-sprint protocols during each experimental condition: 10 × 15-m linear sprints without a change of direction, 10 × 15-m sprints incorporating one 180-degree change of direction, or 10 × 15-m sprints incorporating two 180-degree changes of direction. A 30-second passive recovery period was provided between repetitions. Total sprint distance, number of repetitions, and recovery duration were standardized across the three conditions; only the number of changes of direction differed. Sprint times were recorded using electronic timing gates. Best, average, and worst sprint times were determined, and sprint decrement and the change from best to worst performance were calculated. Rating of perceived exertion was recorded after each protocol. Heart rate, peripheral oxygen saturation, and systolic and diastolic blood pressure were assessed immediately before and after each condition. The experimental conditions were compared to determine whether increasing the number of 180-degree changes of direction altered absolute repeated-sprint performance, performance maintenance, perceived exertion, or immediate cardiovascular responses.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
20
Following a standardized 20-minute dynamic warm-up, participants performed 10 maximal 15-m linear sprints without a change of direction. Each sprint began from a standing position 0.5 m behind the starting line and was recorded using electronic timing gates. A 30-second passive recovery period was provided between repetitions, during which participants remained standing.
Following a standardized 20-minute dynamic warm-up, participants performed 10 maximal 15-m repeated sprints. Each repetition consisted of 7.5 m of forward sprinting followed by one 180-degree change of direction and a 7.5-m return sprint. Each sprint began from a standing position 0.5 m behind the starting line and was recorded using electronic timing gates. A 30-second passive recovery period was provided between repetitions, during which participants remained standing.
Following a standardized 20-minute dynamic warm-up, participants performed 10 maximal 15-m repeated sprints. Each repetition consisted of three consecutive 5-m sections and incorporated two 180-degree changes of direction. Each sprint began from a standing position 0.5 m behind the starting line and was recorded using electronic timing gates. A 30-second passive recovery period was provided between repetitions, during which participants remained standing.
Pamukkale University Sports Sciences and Technology Research and Application Center
Denizli, Pamukkale, Turkey (Türkiye)
Average Sprint Time
The mean completion time of the 10 maximal 15-m sprint repetitions, recorded using Witty electronic timing gates and expressed in seconds. The outcome was calculated separately for the linear, one-COD, and two-COD repeated-sprint conditions.
Time frame: During the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
Best Sprint Time
The fastest completion time (lowest value) among the 10 maximal 15-m sprint repetitions, recorded using Witty electronic timing gates and expressed in seconds. The outcome was determined separately for the linear, one-COD, and two-COD repeated-sprint conditions.
Time frame: During the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
Worst Sprint Time
The slowest completion time (highest value) among the 10 maximal 15-m sprint repetitions, recorded using Witty electronic timing gates and expressed in seconds. The outcome was determined separately for the linear, one-COD, and two-COD repeated-sprint conditions.
Time frame: During the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
Sprint Decrement
The percentage reduction in performance across the 10 maximal sprint repetitions. Sprint decrement was calculated separately for each experimental condition using the following formula: Sdec (%) = (\[sum of the 10 sprint times / (best sprint time × 10)\] - 1) × 100. Higher values indicate a greater decline in repeated-sprint performance.
Time frame: Calculated from the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
Worst-to-Best Decrement
The percentage difference between the fastest and slowest sprint repetitions, calculated separately for each experimental condition using the following formula: \[(worst sprint time - best sprint time) / best sprint time\] × 100. Higher values indicate a greater decline from the best to the worst performance.
Time frame: Calculated from the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
Rating of Perceived Exertion
Perceived exertion was assessed using the Borg category-ratio scale ranging from 0 to 10, where 0 represents rest and 10 represents maximal exertion. Participants rated the overall difficulty of each completed repeated-sprint condition.
Time frame: Immediately after completion of the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
Heart Rate
Heart rate was measured using a Soulfix fingertip pulse oximeter placed on the index finger of the left hand. Values were recorded in beats per minute before and immediately after each repeated-sprint condition.
Time frame: Immediately before and immediately after the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
Peripheral Oxygen Saturation
Peripheral oxygen saturation (SpO2) was measured using a Soulfix fingertip pulse oximeter placed on the index finger of the left hand. Values were recorded as a percentage before and immediately after each repeated-sprint condition.
Time frame: Immediately before and immediately after the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
Systolic Blood Pressure
Systolic blood pressure was measured on the left upper arm using an Omron M2 Essential automated digital blood-pressure monitor. Values were recorded in millimeters of mercury (mmHg) before and immediately after each repeated-sprint condition.
Time frame: Immediately before and immediately after the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
Diastolic Blood Pressure
Diastolic blood pressure was measured on the left upper arm using an Omron M2 Essential automated digital blood-pressure monitor. Values were recorded in millimeters of mercury (mmHg) before and immediately after each repeated-sprint condition.
Time frame: Immediately before and immediately after the repeated-sprint protocol in Sessions 1, 2, and 3 on Study Days 1, 3, and 5, respectively.
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