An observational study in Hamstring Injury, sponsored by Gdansk University of Physical Education and Sport. Recruiting at 1 site in Poland. Open to participants aged 19 Years to 40 Years. Per ClinicalTrials.gov, last updated 2026-03-25.
Sponsored by Gdansk University of Physical Education and Sport · Observational
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.
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
Gdansk University of Physical Education and Sport is the lead sponsor of 37 studies on the registry; 11 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Physically active individuals aged 19-40 years, performing a minimum of two training sessions per week.
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Exclusion Criteria:
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Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The participants will be randomly assigned to four research groups. The first research group will undergo a four-week Nordic Hamstring Exercise training program combined with Super Inductive Stimulation applied to the hamstring muscle group. The second research group will perform a four-week Nordic Hamstring Exercise training program. The third research group will undergo a four-week series of Super Inductive Stimulation sessions applied to the hamstring muscle group. The fourth group, which will serve as the control group, will not change their physical activity habits.
Other: Nordic Hamstring Exercises + SIS stimulation
The participants will be randomly assigned to four research groups. The first research group will undergo a four-week plyometric training program combined with Super Inductive Stimulation applied to the hamstring muscle group. The second research group will perform a four-week plyometric training program. The third research group will undergo a four-week series of Super Inductive Stimulation sessions applied to the hamstring muscle group. The fourth group, which will serve as the control group, will not change their physical activity habits.
Other: Plyometric traning + SIS stimulation
The participants will be randomly assigned to four research groups. The first research group will undergo a four-week neuromuscular training program combined with Super Inductive Stimulation applied to the hamstring muscle group. The second research group will perform a four-week neuromuscular training program. The third research group will undergo a four-week series of Super Inductive Stimulation sessions applied to the hamstring muscle group. The fourth group, which will serve as the control group, will not change their physical activity habits.
Other: Neuromuscular traning + SIS stimulation
Super Inductive Stimulation (SIS) uses a high-intensity electromagnetic field (28 kT/s). The stimulus, induced by a coil placed in the applicator, generates depolarization of neuromuscular tissue. As a result, SIS evokes an action potential in the neuromuscular tissue, leading to the strengthening of weakened muscles. Due to the methodology of this intervention, the procedures are performed once per week over a period of 4 weeks.
Other: Super Inductive Stimulation (SIS) Intervention
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.
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.
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.
uses a high-intensity electromagnetic field (28 kT/s). The stimulus, induced by a coil placed in the applicator, generates depolarization of neuromuscular tissue
Medial-Lateral Stability Index (MLSI)
Assessment of medial-lateral postural stability using a balance platform
Time frame: Baseline and immediately post-intervention (Week 4)
Overall Stability Index (OSI)
Assessment of overall postural stability using a balance platform
Time frame: Baseline and immediately post-intervention (Week 4)
Anteroposterior Stability Index (APSI)
Assessment of anteroposterior postural stability using a balance platform
Time frame: Baseline and immediately post-intervention (Week 4)
Maximal hamstring muscle strength
Maximal voluntary strength of the hamstring muscles will be assessed bilaterally using a standardized strength testing protocol
Time frame: Baseline and immediately post-intervention (Week 4)
Plan to share: No
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Started Mar 2025 (actual). Primary completion is estimated for May 2026, 13 months after the start.
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Gdansk University of Physical Education and Sport