Acute Effects of Different Warm-Up Protocols in Amateur Basketball Players

This study is designed as a single-center, three-arm, parallel-group, assessor-blinded randomized controlled trial investigating the acute effects of different warm-up and proprioceptive neuromuscular facilitation (PNF) stretching protocols in male amateur basketball players.

Forty-five licensed amateur basketball players aged 15 to 25 years will be enrolled and randomly allocated in a 1:1:1 ratio to one of the following groups:

Standard dynamic warm-up Standard dynamic warm-up followed by classical hold-relax PNF stretching Standard dynamic warm-up followed by short-duration self-administered PNF stretching Randomization will be performed using a computer-generated block randomization sequence prepared by an independent researcher who will not participate in outcome assessment. Group assignments will be concealed in sequentially numbered, opaque, sealed envelopes. The investigator conducting the performance assessments will be blinded to group allocation.

All participants will first perform a standardized dynamic warm-up lasting approximately 10 minutes. The program will include light jogging, high knees, butt kicks, walking lunges, side shuffles, carioca running, multidirectional leg swings, and short progressive acceleration runs.

Participants assigned to the classical PNF group will subsequently receive therapist-administered hold-relax PNF stretching for the hamstrings, quadriceps, gastrocnemius, and hip flexor muscles. Each muscle group will undergo a 6-second submaximal isometric contraction followed by a 20-second passive stretch, repeated three times bilaterally.

Participants assigned to the short-duration self-PNF group will perform supervised self-administered PNF exercises targeting the same muscle groups. Each cycle will include brief agonist or antagonist muscle contractions combined with a short stretching phase. Four repetitions will be completed for each muscle group.

Outcome assessments will be conducted at three time points:

Before the assigned intervention Within the first two minutes after completion of the intervention Fifteen minutes after completion of the intervention The primary outcome will be countermovement jump height, which will be used as an indicator of lower-extremity explosive performance. Secondary outcomes will include squat jump height, 20-meter sprint time, T-test agility performance, Illinois agility performance, Y Balance Test results, sit-and-reach flexibility, active knee flexion range of motion, and perceived exertion.

All interventions and assessments will be completed during a single session lasting approximately 60 to 75 minutes. Testing will be conducted under standardized environmental conditions using the same equipment and assessment order. Participants will be instructed to avoid strenuous exercise before testing and to refrain from alcohol, energy drinks, pre-workout products, and other ergogenic supplements that could influence performance.

The study will examine whether short-duration self-administered PNF stretching can provide flexibility benefits without adversely affecting jump, sprint, agility, and balance performance. The findings may help sports physiotherapists, trainers, and coaches select evidence-based warm-up strategies for amateur basketball players.

Inclusion criteria

• Male
• Aged 15-25 years
• Licensed amateur basketball player
• Minimum 2 years of basketball experience
• Basketball training at least 3 days per week
• No serious lower-extremity injury within the past 6 months
• No lower-extremity surgery within the past 6 months
• No acute pain or movement limitation
• No neurological, vestibular, cardiovascular, or respiratory disorder preventing exercise
• No strenuous exercise or official competition within the past 48 hours No alcohol consumption within the past 24 hours No caffeine, energy drinks, pre-workout products, or ergogenic supplements on the testing day
• Written informed consent
• Parental consent and participant assent for participants younger than 18 years

Exclusion criteria

• Acute lower-extremity muscle, tendon, ligament, or bone injury
• Knee, hip, or ankle surgery within the past 6 months
• History of major ligament, meniscal, or Achilles tendon injury
• Lumbar disc herniation, sciatica, peripheral nerve injury, or neurological disorder
• Vestibular disorder or balance impairment
• Hypertension, serious cardiovascular disease, or exercise contraindication
• Physiotherapy or lower-extremity rehabilitation within the past 3 months
• Regular structured lower-extremity stretching
• Acute infection, fever, or poor general health on the testing day
• Inability to complete the intervention or performance tests