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NCT Number: NCT07492732

Comparison of the Effects of Selected Training Methods and SIS Stimulation on Balance, Motor Tests, and Strength

The purpose of this study is to evaluate the effects of four-week training interventions-Nordic Hamstring Exercise, plyometric training, and neuromuscular training-combined with Super Inductive Stimulation (SIS) on hamstring muscle strength, balance, and motor performance.

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Key information

Conditions

Hamstring Injury

Age range

19 year–40 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Gdansk University of Physical Education and Sport

Gdansk, 80-336, Poland

Location status: Recruiting

Location contact

Ewelina Perzanowska, PhD

CONTACT

[email protected]

791597673

About this study

This randomized controlled study evaluates the effects of three four-week training interventions-Nordic Hamstring Exercise, plyometric training, and neuromuscular training-performed alone or in combination with Super Inductive Stimulation (SIS) in physically active adults.

The study is conducted in three independent stages, each corresponding to a specific training modality. Within each stage, participants are randomly allocated to one of four parallel groups: (1) training combined with SIS, (2) training only, (3) SIS only, or (4) control (no change in habitual physical activity). This design enables assessment of both isolated and combined effects of exercise and electromagnetic stimulation.

All interventions are delivered over a four-week period under supervision. Training protocols are standardized and specific to the intervention type, targeting eccentric strength (Nordic Hamstring Exercise), explosive performance (plyometric training), or neuromuscular control (neuromuscular training).

SIS is applied to the hamstring muscle group using a high-intensity electromagnetic stimulation device, with standardized parameters across participants.

A familiarization phase is conducted prior to the intervention to ensure consistency in procedures. Adherence and protocol compliance are monitored throughout the study.

This study aims to determine the relative and combined effectiveness of these interventions in improving neuromuscular performance in physically active individuals

Who can participate

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy individuals aged 19-40,
  • Without injuries,
  • Physically active persons, athletes.

Exclusion criteria

  • periods of peak training load specific to the athlete's discipline,
  • evidence of overload-related pathology in the knee, hip, or lumbosacral joints,
  • the presence of any pain symptoms,
  • clinically relevant muscle fatigue or indicators of overtraining,
  • engagement in strength-based sports within several weeks preceding competition,
  • active inflammatory conditions involving osseous, articular, or ligamentous structures of the lower limbs,
  • a history of injury or surgical intervention within the 6 months prior to the study intervention.

Treatment and study plan

Nordic Hamstring Exercises + SIS stimulation

Other

Nordic Hamstring Exercise training lasts 4 weeks, during which the participant performs 3 sets, each consisting of 3 repetitions of the NHE. After each set, a 2-minute passive rest period follows, during which the participant recovers. In the first week, the participant trains under the supervision of the instructor, while in the following three weeks the exercises are performed at home after prior instruction.

Plyometric traning + SIS stimulation

Other

The intervention lasts 4 weeks, during which participants train three times per week. The program consists of single-leg and double-leg jumps, vertical jumps, lateral jumps, and forward jumps, all performed on a stable surface. A principle of progressive overload is applied, with gradual increases in training intensity, volume, and jump height. The progression begins with lower intensity exercises, single-joint movements, and less complex techniques, and advances to higher intensity exercises, multi-joint movements, and more complex techniques.

Neuromuscular traning + SIS stimulation

Other

The intervention lasts 4 weeks, with participants training three times per week. The program focuses on improving dynamic stability and incorporates the use of BOSU equipment. Exercises include multitask movements performed on unstable surfaces as well as exercises with eyes closed. During the first week, exercises are performed on a stable surface to improve balance while standing on one leg with eyes open and closed. In the following weeks, exercises on unstable surfaces are introduced, emphasizing the maintenance of proper posture on either one or both legs during multitask activities. In the third week, dynamic exercises on unstable surfaces are added, such as single-leg squats. In the final week, jumps and hops are incorporated. To further increase difficulty, additional load is introduced in the form of medicine balls weighing between 2 and 8 kilograms.

Super Inductive Stimulation (SIS) Intervention

Other

uses a high-intensity electromagnetic field (28 kT/s). The stimulus, induced by a coil placed in the applicator, generates depolarization of neuromuscular tissue

Primary outcomes

  1. Medial-Lateral Stability Index (MLSI)

    Time frame: Baseline and immediately post-intervention (Week 4)

    Assessment of medial-lateral postural stability using a balance platform

  2. Overall Stability Index (OSI)

    Time frame: Baseline and immediately post-intervention (Week 4)

    Assessment of overall postural stability using a balance platform

  3. Anteroposterior Stability Index (APSI)

    Time frame: Baseline and immediately post-intervention (Week 4)

    Assessment of anteroposterior postural stability using a balance platform

  4. Maximal hamstring muscle strength

    Time frame: Baseline and immediately post-intervention (Week 4)

    Maximal voluntary strength of the hamstring muscles will be assessed bilaterally using a standardized strength testing protocol

Study contacts

Contact information is provided by the study sponsor or research team.

Ewelina Perzanowska, PhD

CONTACT

[email protected]

791597673

Sponsors and collaborators

Lead sponsor

Gdansk University of Physical Education and Sport

Other

Registry information

Official study title

Comparison of the Effects of Selected Training Methods (Neuromuscular Training, Plyometric Training, and Nordic Hamstring Exercise) and SIS Stimulation on Balance, Motor Performance Tests, and Lower Limb Strength

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Mar 25, 2026
Registry last updated
Mar 25, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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