Aquatic Plyometrics for Adolescents With Patellofemoral Pain Syndrome

Hydro-Kinetic Plyometrics: A Randomized Clinical Assessment of Its Therapeutic Benefits for Adolescents With Patellofemoral Pain Syndrome

This study was designed to assess the effect of a 12-week hydro-kinetic plyometric (HK-Plyo) training on pain, muscle strength, disability, and quality of life (QoL) in adolescents with patellofemoral pain syndrome (PFPS). Fifty-six adolescents with PFPS were randomly allocated to the HK-Plyo group (n = 28, received the plyometric-based hydro-kinetic therapy program, twice/week, over 12 weeks) or the control group (n = 28, received standard exercise program). Both groups were assessed for pain, muscle strength, disability, and QoL pre and post-treatment.

Study Overview

• Status: Completed
• Conditions: Patellofemoral Pain Syndrome
• Intervention / Treatment: Other: Hydro-Kinetic Plyometric Exercise Program; Other: Standard Exercise Program (Conventional Physical Therapy)

Detailed Description

Fifty-six adolescents diagnosed with PFPS were recruited from three major tertiary-care hospitals in Riyadh, Saudi Arabia. Inclusion criteria comprised individuals aged 10 to 18 years with a confirmed PFPS diagnosis (ICD-10 code: M22.2X9). Participants were required to present with chronic pain (>3 months in duration) scoring greater than 3 on a 0-to-10 numeric pain scale, which was exacerbated by physical activity and alleviated by rest. Exclusion criteria encompassed a history of knee surgery, acute knee trauma, patellar subluxation or dislocation, and the use of corticosteroids or anti-inflammatory medications within the preceding six months.

Outcome Measures

Pain Intensity: Assessed during both rest and physical movement using the 11-point Numerical Pain Rating Scale (NPRS), where 0 indicates "no pain" and 10 indicates "worst pain imaginable."

Muscle Strength: Measured as peak concentric torque (in Newton-meters [Nm]) of the quadriceps and hamstring muscle groups using an isokinetic dynamometer at an angular velocity of 120°/sec and 180°/sec.

Functional Disability: Evaluated using the Patellofemoral Disability Index (PDI), a self-reported questionnaire that measures the degree of functional limitation and difficulty an adolescent experiences when performing daily activities due to knee pain.

Quality of Life (QoL): Assessed using the Arabic version of the MOS 36-Item Short Form Health Survey (SF-36), a standardized patient-reported survey that evaluates physical and mental health components across eight health domains.

Interventions

The HK-Polyo group underwent a structured HK-Plyo program conducted in a water medium (pool). The intervention consisted of 24 total sessions, delivered twice a week for 12 consecutive weeks. Each 45-minute session included a 10-minute aquatic warm-up, a 30-minute core plyometric phase, and a 5-minute cool-down. The core phase consisted of 10 unilateral and bilateral lower-limb plyometric exercises, including variations of hopping, bounding, and jumping. Exercise prescription, progression, and safety parameters strictly adhered to the National Strength and Conditioning Association (NSCA) guidelines and the American Academy of Pediatrics (AAP) safety standards.

The control group underwent a standard, land-based exercise program. The intervention consisted of 24 total sessions, delivered twice a week for 12 consecutive weeks, with each session lasting 45 minutes. The program was multimodal and consisted of lower-limb flexibility exercises, progressive lower-extremity strength training, weight-bearing exercises, proprioceptive training, and balance exercises.

• Study Type: Interventional
• Enrollment (Actual): 56
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Saudi Arabia
  • Riyadh Region
    • Al Kharj, Riyadh Region, Saudi Arabia
      • Ragab K. Elnaggar

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age of 10-18 years
2. Verified diagnosis of PFPS based on the ICD classification system (ICD-10 code for PFPS: M22.2X9)
3. Pain more than 3 on (0-10 pain scale).
4. Persistent pain more than 3 months
5. Pain get worse with activities and get better with rest.

Exclusion Criteria:

1. History of knee surgery
2. Recent trauma
3. Corticosteroids or anti-inflammatory medications in the past 6 months
4. Patellar subluxation or dislocation

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: Control group; Participants in this group received the standard exercise program.	Other: Standard Exercise Program (Conventional Physical Therapy); Participants underwent a standard, land-based exercise program. The intervention consisted of 24 total sessions, delivered twice a week for 12 consecutive weeks, with each session lasting 45 minutes. The program was multimodal and consisted of lower-limb flexibility exercises, progressive lower-extremity strength training, weight-bearing exercises, proprioceptive training, and balance exercises.
Experimental: HK-Plyo group; Participants in this group underwent a structured HK-Plyo program.	Other: Hydro-Kinetic Plyometric Exercise Program; Participants underwent a structured HK-Plyo program conducted in a water medium (pool). The intervention consisted of 24 total sessions, delivered twice a week for 12 consecutive weeks. Each 45-minute session included a 10-minute aquatic warm-up, a 30-minute core plyometric phase, and a 5-minute cool-down. The core phase consisted of 10 unilateral and bilateral lower-limb plyometric exercises, including variations of hopping, bounding, and jumping. Exercise prescription, progression, and safety parameters strictly adhered to the National Strength and Conditioning Association (NSCA) guidelines and the American Academy of Pediatrics (AAP) safety standards.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain Intensity	Assessed during both rest and physical movement using the 11-point Numerical Pain Rating Scale (NPRS), where 0 indicates "no pain" and 10 indicates "worst pain imaginable".	1 month
Muscle Strength	Measured as peak concentric torque (in Newton-meters [Nm]) of the quadriceps and hamstring muscle groups using an isokinetic dynamometer at an angular velocity of 120°/sec and 180°/sec.	1 month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional Disability	Functional disability was assessed using the Patellofemoral Disability Index (PDI), a 10-item, self-administered questionnaire designed to quantify the functional limitations adolescents experience during daily activities secondary to knee pain. Responses to each item were recorded on a 6-point ordinal scale ranging from 0 to 5. A score of 0 indicated no functional deficit, while a score of 5 signified severe symptom exacerbation or bedbound status. The intermediate anchors represented a graded spectrum of impairment: 1 (minimal), 2 (minimal-to-moderate), 3 (moderate), and 4 (severe). Individual item scores were summated to generate a total index ranging from 0 to a maximum of 50 points, wherein higher scores denoted progressively greater levels of disability.	1 month
Quality of life (QoL)	Assessed using the Arabic version of the MOS 36-Item Short Form Health Survey (SF-36), a patient-reported instrument consisting of 36 items that evaluate physical and mental health across eight distinct domains. Item-level responses were captured using varying Likert scales, which were subsequently coded and mathematically transformed according to standard SF-36 scoring algorithms. This transformation yielded a standardized score ranging from 0 to a maximum of 100 points for each domain. In this scoring metric, higher scores denoted a more favorable quality of life, whereas lower scores indicated poorer health status.	1 Month

Collaborators and Investigators

• Sponsor: Cairo University
• Collaborators: Prince Sattam Bin Abdulaziz University

Study record dates

Study Major Dates

• Study Start (Actual): June 4, 2023
• Primary Completion (Actual): May 30, 2024
• Study Completion (Actual): May 30, 2024

Study Registration Dates

• First Submitted: June 25, 2026
• First Submitted That Met QC Criteria: June 25, 2026
• First Posted (Actual): July 1, 2026

Study Record Updates

• Last Update Posted (Actual): July 1, 2026
• Last Update Submitted That Met QC Criteria: June 25, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Joint Diseases; Patellofemoral Pain Syndrome
• Other Study ID Numbers: RHPT/0023/0019

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared with other researchers in order to strictly protect the privacy and confidentiality of the adolescent participants involved in this study

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No