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Effects of Microdosed Resistance Training During Physical Education on Health-Related Fitness in Adolescents

21 de septiembre de 2026 actualizado por: Dawid Koźlenia, Wroclaw University of Health and Sport Sciences

Effects of Microdosed Resistance Training During Physical Education Lessons on Health-Related Fitness in School Adolescents

This study will examine whether short bouts of resistance training incorporated into physical education lessons can improve health-related physical fitness in secondary school students aged 15-16 years.

A total of 264 students will participate in two successive cohorts. School classes, rather than individual students, will be randomly assigned to study groups. In the first cohort, three resistance-training programs using low, moderate, or high training loads will be compared with usual physical education. The program producing the most consistent beneficial changes will then be tested in a new group of students in the second cohort and compared with usual physical education.

Each training program will last eight weeks. Participants will be assessed before the intervention, halfway through it, immediately after it, and eight weeks after it ends. Assessments will include body composition, blood pressure, cardiorespiratory fitness, muscular fitness, jumping performance, trunk muscular endurance, and sprint performance.

The study will evaluate both average changes in each group and the proportion of students showing improvements greater than the expected measurement error of the tests.

Descripción general del estudio

Estado

Aún no reclutando

Condiciones

Intervención / Tratamiento

Descripción detallada

This school-based study is designed as a two-stage, cluster-randomized controlled trial consisting of an exploratory cohort followed by a confirmatory cohort. The school class is the unit of randomization. Planned enrollment is 132 students in each cohort, for a total of 264 participants.

In Cohort I, participating classes will be randomized in a 1:1:1:1 ratio to one of four study conditions: low-load resistance training, moderate-load resistance training, high-load resistance training, or usual physical education. The three resistance-training conditions will differ primarily in training load, repetition range, number of sets, rest intervals, and repetitions in reserve.

The resistance-training program showing the highest frequency of beneficial individual responses in Cohort I will be selected for further evaluation. A beneficial individual response will be defined as an improvement exceeding the minimal detectable change (MDC) for the respective outcome. Cohort II will include a new set of school classes randomized in a 1:1 ratio to either the resistance-training program selected from Cohort I or usual physical education.

Randomization will be performed at the class level using permuted blocks. Block size will be four classes in Cohort I and two classes in Cohort II. The sex composition of classes will be considered to support balanced allocation across study conditions. The randomization sequence will be generated using R with a fixed random seed. Participants and physical education teachers cannot be blinded to group assignment. Outcome assessors will remain unaware of class allocation where feasible.

The resistance-training interventions will be incorporated into regular physical education lessons and supervised by physical education teachers. Exercises will use body weight, dumbbells, medicine balls, and resistance bands. Training load will progress every two weeks by modifying repetitions, rest intervals, external resistance, or the number of sets according to the assigned training condition.

Measurements will be performed at four time points: before the intervention, at the intervention midpoint, immediately after the eight-week intervention, and eight weeks after completion of the intervention. Assessments will include anthropometric measures, body composition assessed by bioelectrical impedance analysis, resting blood pressure, cardiorespiratory fitness assessed using the 20-m shuttle run test, handgrip strength, countermovement jump performance, standing long jump performance, 30-second sit-up performance, and 10-m sprint performance. Somatic maturation, injury history, dietary habits, rating of perceived exertion, and repetitions in reserve will also be recorded.

Statistical analyses will account for repeated measurements and the clustering of students within school classes. Mixed-effects approaches, including linear mixed models and generalized linear mixed models where appropriate, will be used to evaluate changes over time and differences between study groups. Individual responsiveness will additionally be evaluated using outcome-specific MDC thresholds.

Tipo de estudio

Intervencionista

Inscripción (Estimado)

264

Fase

  • No aplica

Contactos y Ubicaciones

Esta sección proporciona los datos de contacto de quienes realizan el estudio e información sobre dónde se lleva a cabo este estudio.

Estudio Contacto

Criterios de participación

Los investigadores buscan personas que se ajusten a una determinada descripción, denominada criterio de elegibilidad. Algunos ejemplos de estos criterios son el estado de salud general de una persona o tratamientos previos.

Criterio de elegibilidad

Edades elegibles para estudiar

15 años a 18 años (Niño, Adulto)

Acepta Voluntarios Saludables

Sí

Géneros elegibles para el estudio

Todos

Descripción

Inclusion Criteria:

  • Enrollment in the second year of a participating secondary school.
  • Participation in regular physical education lessons at the participating school.
  • No health contraindications to physical exercise.
  • Written informed consent from the participant and, for participants who are minors, written informed consent from a parent or legal guardian.

Exclusion Criteria:

  • Acute or chronic musculoskeletal injury preventing safe participation in the exercise intervention or physical fitness assessments.
  • Chronic disease or other medical condition constituting a contraindication to physical exercise.
  • Medical recommendation limiting participation in physical activity.
  • Acute infection or other temporary health condition preventing safe participation in a scheduled assessment.
  • Lack of the required informed consent.

Plan de estudios

Esta sección proporciona detalles del plan de estudio, incluido cómo está diseñado el estudio y qué mide el estudio.

¿Cómo está diseñado el estudio?

Detalles de diseño

  • Propósito principal: Otro
  • Asignación: Aleatorizado
  • Modelo Intervencionista: Asignación Secuencial
  • Enmascaramiento: Único

Armas e Intervenciones

Grupo de participantes/brazo
Intervención / Tratamiento
Experimental: Cohort I: Low-Load Resistance Training

Teacher-supervised resistance training incorporated into physical education lessons for eight weeks. Exercises use body weight, dumbbells, medicine balls, and resistance bands. The initial prescription consists of 2-3 sets of 12-15 repetitions, 30-40 seconds of rest between sets, and 3-4 repetitions in reserve. Training progresses every two weeks through planned changes in repetitions, rest intervals, external resistance, or number of sets.

Teacher-supervised resistance training incorporated into physical education over eight weeks using body weight, dumbbells, medicine balls, and resistance bands. Cohort I compares three prescriptions: low-load (2-3 sets, 12-15 repetitions, 30-40 s rest, 3-4 repetitions in reserve), medium-load (3-4 sets, 8-12 repetitions, about 60 s rest, 2-3 repetitions in reserve), and high-load (4-5 sets, 6-8 repetitions, about 90 s rest, 1-2 repetitions in reserve). Progression occurs every two weeks through changes in repetitions, rest, external resistance, or sets. Cohort II receives the program selected from Cohort I based on the frequency of improvements exceeding minimal detectable change.

Experimental: Cohort I: Moderate-Load Resistance Training

Teacher-supervised resistance training incorporated into physical education lessons for eight weeks. Exercises use body weight, dumbbells, medicine balls, and resistance bands. The initial prescription consists of 3-4 sets of 8-12 repetitions, approximately 60 seconds of rest between sets, and 2-3 repetitions in reserve. Training progresses every two weeks through planned changes in repetitions, rest intervals, external resistance, or number of sets.

Teacher-supervised resistance training incorporated into physical education over eight weeks using body weight, dumbbells, medicine balls, and resistance bands. Cohort I compares three prescriptions: low-load (2-3 sets, 12-15 repetitions, 30-40 s rest, 3-4 repetitions in reserve), medium-load (3-4 sets, 8-12 repetitions, about 60 s rest, 2-3 repetitions in reserve), and high-load (4-5 sets, 6-8 repetitions, about 90 s rest, 1-2 repetitions in reserve). Progression occurs every two weeks through changes in repetitions, rest, external resistance, or sets. Cohort II receives the program selected from Cohort I based on the frequency of improvements exceeding minimal detectable change.

Experimental: Cohort I: High-Load Resistance Training

Teacher-supervised resistance training incorporated into physical education lessons for eight weeks. Exercises use body weight, dumbbells, medicine balls, and resistance bands. The initial prescription consists of 4-5 sets of 6-8 repetitions, approximately 90 seconds of rest between sets, and 1-2 repetitions in reserve. Training progresses every two weeks through planned changes in repetitions, rest intervals, external resistance, or number of sets.

Teacher-supervised resistance training incorporated into physical education over eight weeks using body weight, dumbbells, medicine balls, and resistance bands. Cohort I compares three prescriptions: low-load (2-3 sets, 12-15 repetitions, 30-40 s rest, 3-4 repetitions in reserve), medium-load (3-4 sets, 8-12 repetitions, about 60 s rest, 2-3 repetitions in reserve), and high-load (4-5 sets, 6-8 repetitions, about 90 s rest, 1-2 repetitions in reserve). Progression occurs every two weeks through changes in repetitions, rest, external resistance, or sets. Cohort II receives the program selected from Cohort I based on the frequency of improvements exceeding minimal detectable change.

Sin intervención: Cohort I: Usual Physical Education

Students assigned to the control arm will continue their usual school physical education lessons for eight weeks and will not receive the study-specific resistance training microdosing intervention.

Experimental: Cohort II: Selected Resistance Training Program

Teacher-supervised resistance training incorporated into physical education lessons for eight weeks. The program will be the low-, moderate-, or high-load resistance training protocol selected after completion of Cohort I according to the prespecified criterion of the highest frequency of beneficial individual responses exceeding the minimal detectable change in the assessed health-related fitness outcomes. The selected protocol will be implemented in a new set of school classes in Cohort II

Teacher-supervised resistance training incorporated into physical education over eight weeks using body weight, dumbbells, medicine balls, and resistance bands. Cohort I compares three prescriptions: low-load (2-3 sets, 12-15 repetitions, 30-40 s rest, 3-4 repetitions in reserve), medium-load (3-4 sets, 8-12 repetitions, about 60 s rest, 2-3 repetitions in reserve), and high-load (4-5 sets, 6-8 repetitions, about 90 s rest, 1-2 repetitions in reserve). Progression occurs every two weeks through changes in repetitions, rest, external resistance, or sets. Cohort II receives the program selected from Cohort I based on the frequency of improvements exceeding minimal detectable change.

Sin intervención: Cohort II: Usual Physical Education

New classes assigned to the control arm will continue their usual school physical education lessons for eight weeks and will not receive the study-specific resistance training microdosing intervention.

¿Qué mide el estudio?

Medidas de resultado primarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Change in Body Fat Percentage
Periodo de tiempo: Baseline, week 4, week 8, and week 16

Body fat percentage will be assessed using bioelectrical impedance analysis. Measurements will be obtained at baseline, week 4, week 8, and week 16. Change from baseline at each post-baseline assessment will be analyzed and expressed in percentage points.

Baseline, week 4, week 8, and week 16
Change in Muscle Mass
Periodo de tiempo: Baseline, week 4, week 8, and week 16

Muscle mass will be assessed using bioelectrical impedance analysis. Measurements will be obtained at baseline, week 4, week 8, and week 16. Change from baseline at each post-baseline assessment will be analyzed.

Baseline, week 4, week 8, and week 16
Change in Systolic Blood Pressure
Periodo de tiempo: Baseline, week 4, week 8, and week 16

Systolic blood pressure will be measured after five minutes of seated rest. Three measurements will be obtained at each assessment, and the mean of the three measurements will be used for analysis. Change from baseline at each post-baseline assessment will be analyzed.

Baseline, week 4, week 8, and week 16
Change in Diastolic Blood Pressure
Periodo de tiempo: Baseline, week 4, week 8, and week 16

Diastolic blood pressure will be measured after five minutes of seated rest. Three measurements will be obtained at each assessment, and the mean of the three measurements will be used for analysis. Change from baseline at each post-baseline assessment will be analyzed.

Baseline, week 4, week 8, and week 16
Change in Estimated Maximal Oxygen Uptake
Periodo de tiempo: Baseline, week 8

Cardiorespiratory fitness will be assessed using the 20-m shuttle run test. Maximal oxygen uptake (VO2max) will be estimated from test performance. Measurements will be obtained at baseline, week 4, week 8, and week 16, and change from baseline will be analyzed.

Baseline, week 8
Change in Handgrip Strength
Periodo de tiempo: Baseline, week 4, week 8, and week 16

Isometric handgrip strength will be assessed using a handgrip dynamometer. Measurements will be obtained at baseline, week 4, week 8, and week 16. Change from baseline at each post-baseline assessment will be analyzed.

Baseline, week 4, week 8, and week 16
Change in Countermovement Jump Performance
Periodo de tiempo: Baseline, week 4, week 8, and week 16

Vertical lower-limb power will be assessed using the countermovement jump. Jump height will be recorded at baseline, week 4, week 8, and week 16. Change from baseline at each post-baseline assessment will be analyzed.

Baseline, week 4, week 8, and week 16
Change in Standing Long Jump Performance
Periodo de tiempo: Baseline, week 4, week 8, and week 16

Horizontal lower-limb power will be assessed using the standing long jump. Jump distance will be recorded at baseline, week 4, week 8, and week 16. Change from baseline at each post-baseline assessment will be analyzed.

Baseline, week 4, week 8, and week 16
Change in 30-Second Sit-Up Performance
Periodo de tiempo: Baseline, week 4, week 8, and week 16

Trunk muscular endurance will be assessed using a 30-second sit-up test. The number of correctly completed repetitions will be recorded at baseline, week 4, week 8, and week 16. Change from baseline at each post-baseline assessment will be analyzed.

Baseline, week 4, week 8, and week 16
Change in 10-m Sprint Performance
Periodo de tiempo: Baseline, week 4, week 8, and week 16

Locomotor speed and acceleration will be assessed using a 10-m sprint measured with photocells. Two trials will be performed, and the best performance will be used for analysis. Measurements will be obtained at baseline, week 4, week 8, and week 16, and change from baseline will be analyzed.

Baseline, week 4, week 8, and week 16

Colaboradores e Investigadores

Aquí es donde encontrará personas y organizaciones involucradas en este estudio.

Patrocinador

Colaboradores

Investigadores

  • Investigador principal: Dawid Koźlenia, PhD, Wroclaw University of Health and Sport Sciences

Fechas de registro del estudio

Estas fechas rastrean el progreso del registro del estudio y los envíos de resultados resumidos a ClinicalTrials.gov. Los registros del estudio y los resultados informados son revisados ​​por la Biblioteca Nacional de Medicina (NLM) para asegurarse de que cumplan con los estándares de control de calidad específicos antes de publicarlos en el sitio web público.

Fechas importantes del estudio

Inicio del estudio (Estimado)

1 de noviembre de 2026

Finalización primaria (Estimado)

1 de abril de 2028

Finalización del estudio (Estimado)

1 de abril de 2028

Fechas de registro del estudio

Enviado por primera vez

21 de septiembre de 2026

Primero enviado que cumplió con los criterios de control de calidad

21 de septiembre de 2026

Publicado por primera vez (Actual)

29 de septiembre de 2026

Actualizaciones de registros de estudio

Última actualización publicada (Actual)

29 de septiembre de 2026

Última actualización enviada que cumplió con los criterios de control de calidad

21 de septiembre de 2026

Última verificación

1 de septiembre de 2026

Más información

Términos relacionados con este estudio

Otros números de identificación del estudio

  • NdRS/SP/0160/2025/01
  • NdRS/SP/0160/2025/01 (Otro número de subvención/financiamiento: inistry of Science and Higher Education, Poland)

Plan de datos de participantes individuales (IPD)

¿Planea compartir datos de participantes individuales (IPD)?

SÍ

Descripción del plan IPD

De-identified individual participant data underlying the results reported in study publications may be shared with qualified researchers upon reasonable request to the Principal Investigator, subject to applicable data protection regulations, institutional requirements, and the conditions of informed consent. No directly identifiable participant information will be shared.

Información sobre medicamentos y dispositivos, documentos del estudio

Estudia un producto farmacéutico regulado por la FDA de EE. UU.

No

Estudia un producto de dispositivo regulado por la FDA de EE. UU.

No

Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .