Effects of Combining PNF With NMES in Young Basketball Players (PNF+NMES)

Short Term Effects of Proprioceptive Neuromuscular Facilitation Combined With Neuromuscular Electrical Stimulation in Young Basketball Players: a Randomized Clinical Trial.

Hamstring muscle injuries are common in basketball and result in long periods of inactivity. This study aims to compare two different stretching programs to assess their effects on hamstring flexibility and, secondarily, on jumping ability in young basketball players. One program uses a special stretching technique called proprioceptive neuromuscular facilitation (PNF), while the other uses the same stretching but adds electrical stimulation (NMES).

Study Overview

• Status: Completed
• Conditions: Hamstring Flexibility
• Intervention / Treatment: Other: Contract-Relax PNF (crPNF); Other: Neuromuscular electrical stimulation (NMES)

Detailed Description

Hamstring strains are increasingly common in sports, particularly in football and professional basketball, where they are the fourth most frequent injury. Stretching, especially when combined with techniques like proprioceptive neuromuscular facilitation (PNF), is a key method used to reduce the risk of these injuries. PNF, which involves alternating stretches with muscle contractions, is widely regarded for improving muscle flexibility. Recently, stretching combined with neuromuscular electrical stimulation (NMES) has also shown promise for increasing flexibility. A variant of PNF called contract-relax PNF (crPNF) has been proposed, where NMES is applied during the contraction phase to further enhance flexibility gains. However, there are no studies on the short-term effects of crPNF and crPNF + NMES in young male basketball players, a group known for higher degrees of hamstring shortening.

This study aims to compare the short-term effects of crPNF and crPNF + NMES on hamstring flexibility in young male basketball players and assess whether one technique is superior to the other. A secondary goal is to determine if either stretching protocol negatively impacts vertical jump ability, an important skill in basketball.

• Study Type: Interventional
• Enrollment (Actual): 44
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Valencia
    • Alfara del Patriarca, Valencia, Spain, 46113
      • University Ceu Cardenal Herrera

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Active basketball players who train at least 3 days a week
• Ages between 11 and 18 years
• Male gender

Exclusion Criteria:

• Participation in an organized hamstring stretching program
• Presence of low back pain
• Hamstring muscle injuries in the last 6 months
• Spinal or abdominal surgeries in the last 6 months

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: contract-relax proprioceptive neuromuscular facilitation (crPNF); Participants in this group performed a stretching protocol using contract-relax proprioceptive neuromuscular facilitation (crPNF). The participants are placed in a long sitting position with maximum knee extension possible until a moderate-strong stretch sensation is felt, without pain. The stretch lasts for 20 seconds, followed by a maximal voluntary isometric contraction of the hamstrings for 5 seconds. Three stretch-contraction cycles are completed. One researcher maintains the stretch position, while a second researcher controls the stretching and contraction times.	Other: Contract-Relax PNF (crPNF); The crPNF Group engages in an isolated contract-relax proprioceptive neuromuscular facilitation (crPNF) stretching protocol. Participants are positioned in a long sitting posture with maximum knee extension until they feel a moderate-strong stretch sensation, without pain. Each stretch lasts for 20 seconds, followed by a 5-second maximal voluntary isometric contraction of the hamstrings. Participants complete three cycles of stretch and contraction. One researcher maintains the stretch position while a second researcher controls the timing of the stretching and contractions.
Experimental: Neuromuscular Electrical Stimulation (NMES + crPNF); The participants follow the same stretching protocol but with neuromuscular electrical stimulation (NMES) added. Electrical stimulation (50Hz, 300 µs pulse width) is applied using an Enraf Nonius TensMed S82 device. Two 5x9 cm electrodes are placed on the hamstrings, and participants adjust the current to a moderate-strong, but painless, contraction. One researcher maintains the stretch, while another adjusts the current intensity and controls the timing of the stretching and contraction.	Other: Contract-Relax PNF (crPNF); The crPNF Group engages in an isolated contract-relax proprioceptive neuromuscular facilitation (crPNF) stretching protocol. Participants are positioned in a long sitting posture with maximum knee extension until they feel a moderate-strong stretch sensation, without pain. Each stretch lasts for 20 seconds, followed by a 5-second maximal voluntary isometric contraction of the hamstrings. Participants complete three cycles of stretch and contraction. One researcher maintains the stretch position while a second researcher controls the timing of the stretching and contractions.; Other: Neuromuscular electrical stimulation (NMES); Neuromuscular electrical stimulation (NMES) is applied during an isometric contraction. The NMES uses a symmetrical biphasic rectangular pulse (50Hz frequency and 300 µs phase width) delivered through an Enraf Nonius TensMed S82 electrostimulator. Two 5x9 cm electrodes are placed on the hamstrings, and participants adjust the current to a moderate-strong, yet painless, contraction level. During the intervention, one researcher maintains the stretch position while another researcher controls the current intensity and monitors the timing of both stretching and contractions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The Popliteal Angle Test	The Popliteal Angle Test is validated for measuring hamstring extensibility. Participants are placed in the supine position. A researcher holds the hip at a 90° flexion and passively extends the knee until the participant feels a strong stretch without pain. The examiner records the knee extension degrees at that moment using an inclinometer. The test is repeated three times, and the average is obtained. A full knee extension corresponds to a value of 0 degrees, and a higher number of degrees indicates greater hamstring shortening.	Before and inmediately after the intervention
The Sit & Reach Test	The Sit & Reach Test has high intra-examiner reliability and is validated for measuring hamstring extensibility. For its execution, participants are placed in a long sitting position with the soles of their feet against the base of the measurement box. Keeping their knees extended, they reach for the maximum possible distance in the box with their fingers. The test is repeated three times, and the average is obtained. Values are recorded in centimeters, where a greater distance indicates a higher degree of hamstring extensibility.	Before and inmediately after the intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The Counter Movement Jump	The Counter Movement Jump is validated and standardized in adolescents for measuring jumping ability. The instructions by Petrigna et al. are followed to perform the jump (Figure 2C). The My Jump App is used, which has high reliability and validity for measuring vertical jump height in centimeters. A greater height indicates a greater jumping ability.	Before and inmediately after the intervention

Collaborators and Investigators

• Sponsor: Cardenal Herrera University
• Investigators: Principal Investigator: Juan Francisco Lisón Párraga, Dr, Cardenal Herrera University

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2024
• Primary Completion (Actual): October 22, 2024
• Study Completion (Actual): October 23, 2024

Study Registration Dates

• First Submitted: October 14, 2024
• First Submitted That Met QC Criteria: October 16, 2024
• First Posted (Actual): October 18, 2024

Study Record Updates

• Last Update Posted (Actual): October 30, 2024
• Last Update Submitted That Met QC Criteria: October 29, 2024
• Last Verified: October 1, 2024

More Information

Terms related to this study

• Keywords: Neuromuscular Electrical Stimulation; vertical jump; basketball; hamstring flexibility; Propioceptive Neuromuscular Facilitation
• Other Study ID Numbers: UNIVERSITY CARDENAL HERRERA-86

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No