Clinical trial NCT06698055: Muscle Adaptations in Children and Adults Following Twelve Weeks of Flywheel or Weight Stack Resistance Exercise
Official title: KidREx - Muscle Adaptations in Children and Adults Following a Twelve-week of Resistance Exercise Period Using Either Flywheel or Traditional Weight Stack Devices - a Randomized Controlled Study
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Resistance Exercise
Muscle Hypertrophy
Skeletal Muscle
EMG
Magnetic Resonance Imaging
Growth Plate Early Closing
Children, Adult
Keywords: Skeletal Muscle
Resistance Exercise
Magnetic Resonance Imaging
EMG
Muscle Hypertrophy
Flywheel Training
Strength Training in Children and Adolescents
Growth Plate
Muscle Adaptation
Muscle Memory
Histology
Immunohistochemistry
Transcriptomics
Methylomics
Proteomics
Functional Outcomes
Physical Activity Monitoring
Physical Self Esteem
Lead sponsor: Region Jönköping County
Sponsor class: OTHER_GOV
Collaborators: name: Karolinska Institutet
name: Umeå University
name: Medical Research Council of Southeast Sweden
name: Swedish Research Council for Sport Science
name: Linkoeping University
name: The Swedish Research Council
First posted: 2024-11-20
Enrollment: 96
Sex: ALL
Minimum age (years): 9
Maximum age (years): 50
Standard ages: CHILD
ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Randomized controlled resistance exercise intervention study
Primary purpose: OTHER

Brief summary: The goal of this trial is to compare resistance exercise using traditional techniques and flywheel training to controls in healthy children ages nine to 13 and adults ages 18 to 50. The main questions it aims to answer are:

* The degree of response to resistance exercise in children compared to adults regarding muscle hypertrophy and strength?
* Is there a negative impact on the physis of children due to resistance exercise?

Participants will be randomized to one of three groups, control, traditional resistance exercise, or flywheel. Following a baseline battery of tests, they will enter a 12-week training period, using leg press and leg extension. Additionally, post-training tests are conducted, and an eight-week detraining period commences followed by new tests. Researchers will compare children and adults and each intervention arm to see if children can achieve muscle hypertrophy, the degree and rate of changes in strength, and the potential impact on the physis.

Detailed description: The KidREx-study is an intervention study aiming to investigate the effects of two alternative forms of resistance exercise on adults and children. Exercise forms include leg press and leg extension, in either traditional weight stack machines or flywheel training machines. It has been proposed and discussed that resistance exercise would cause injury to the growth plate and even premature closure of the physis in children. Multiple studies have shown that this is not the case regarding growth height and radiography of the physis. However, the direct effects of resistance exercise on physis using magnetic resonance imaging are yet to be investigated.

This study is a randomized, controlled, prospective intervention study. Two separate groups (children and adults) are included, children ages 9 to 13 and adults ages 18-50. Participants are randomly assigned to one of six arms for the twelve-week intervention period. Arms include two control groups "living as usual" (children and adults), two flywheel training groups (children and adults), and two weight stack training groups (children and adults). Throughout the intervention period, the training groups conduct a total of 30 sessions (alternating between two or three sessions per week). Following the intervention period, all participants enter an 8-week detraining phase, where no organized resistance training is conducted.

At baseline, all participants conduct a test battery including vertical jump height, horizontal jump length, balance tests, and tests of muscle activity in the specific training machines and in an isokinetic dynamometer. In conjunction with the first exercise bout, venous blood samples are obtained from both adults and children, and skeletal muscle biopsies from m. vastus lateralis are obtained from the adults. This procedure is repeated after 12 weeks of training and following the 8-week detraining period. Outcomes related to this, blood samples and muscle tissue, beyond the fiber-specific hypertrophy, will be subject to ancillary studies.

The investigators hypothesize that weight stack training and flywheel training will result in muscle adaptation in both adults and children, where the rate of adaptation is faster for the flywheel training group. Expected muscle adaptation includes an increase in muscle hypertrophy, strength, and functional strength-related outcomes (balance, vertical jump height, and standing long jump). Additionally, the investigators hypothesize that the growth plate of pre- and intra-pubertal children will not be affected negatively by resistance exercise.

Eligibility criteria: Inclusion Criteria:

* Adults at the age of 18 to 50 at time of inclusion.
* Children at the age of nine to 13 (attending Swedish middle school) at time of inclusion

Exclusion Criteria:

* Neuromuscular disease.
* Previous or current musculoskeletal injury, primarily of the lower limb, preventing resistance exercise.
* Heavy resistance training of the lower limb at inclusion (i.e., more than one session per week of weight training of the lower limb or other equivalent activity)

Primary outcomes:
measure: Change from Baseline Muscle Volume Following 12 Weeks of Resistance Exercies
timeFrame: Time Frame: Before intervention start (0 weeks) and following twelve weeks of training (12 weeks)
Secondary outcomes:
measure: Changes in muscle thickness
timeFrame: Time Frame: Prior to intervention start, biweekly during the intervention period (i.e., after two, four, six and eight weeks). Additional scans will be performed following the end of intervention (12 weeks) and the end of detraining (20 weeks).
measure: Change from baseline in rate of physeal closure following resistance exercise
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Change in muscle volume at 20 weeks
timeFrame: Time Frame: Before intervention start (0 weeks) and end of intervention (12 weeks) compared to volume following the detraining period (20 weeks)]
measure: Changes in peak torque during isokinetic concentric and eccentric knee extension and flexion
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in power during isokinetic concentric and eccentric knee extension and flexion
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in work during isokinetic concentric and eccentric knee extension and flexion
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in muscle activity during isokinetic concentric and eccentric knee extension and flexion measured using sEMG
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in power during flywheel resistance exercise
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in muscle activation with flywheel resistance exercise measured using sEMG
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in power during weight stack resistance exercise
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in muscle activation during weight stack resistance exercise measured using sEMG
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in power output during training
timeFrame: Time Frame: Continuous power measurements during all training sessions, weeks 1 through 12 weeks
measure: Changes in Balance
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in vertical jump height
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in isometric maximum strength
timeFrame: Time Frame: Baseline (0 weeks), 2 weeks of intervention, 4 weeks of intervention, 6 weeks of intervention, 8 weeks of intervention and post intervention (12 weeks) and post detraining (20 weeks)
measure: Changes in standing long jump
timeFrame: Time Frame: Baseline (0 weeks), 2 weeks of intervention, 4 weeks of intervention, 6 weeks of intervention, 8 weeks of intervention and post intervention (12 weeks) and post detraining (20 weeks)
measure: Change in type I-fiber cross-sectional area.
timeFrame: Time Frame: Baseline (0 weeks), two weeks of training, six weeks of training, post training (12 weeks) and post detraining (20 weeks).
measure: Change in type II-fiber cross-sectional area.
timeFrame: Time Frame: Baseline (0 weeks), two weeks of training, six weeks of training, post training (12 weeks) and post detraining (20 weeks).
measure: Changes in testosterone levels in children during the intervention
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in estradiol levels in children during the intervention
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Changes in IGF-1 levels in children during the intervention
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Questionnaire based assessment of physical self-esteem (children)
timeFrame: Time Frame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
Other outcomes:
measure: Activity level (adults)
timeFrame: Time Frame: Starting one week prior to intervention start and ending one week after detraining time point, a total of 22 weeks.
measure: Monitoring of physical activity level (children)
timeFrame: All monitors will be worn for one week at three-time points (baseline, 12 weeks, 20 weeks) during the intervention
measure: Questionnaire based assessment of physical activity (children)
timeFrame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Hand grip strength
timeFrame: Baseline (0 weeks), post training (12 weeks) and post detraining (20 weeks)
measure: Readiness score (sleep quality and quantity through adults)
timeFrame: Time Frame: Starting one week prior to intervention start and ending one g week after detraining time point, a total of 22 weeks.
measure: Monitoring of sleep quality and quantity (children)
timeFrame: All monitors will be worn for one week at three-time points (baseline, 12 weeks, 20 weeks) during the intervention
Locations:
city: Eksjö
country: Sweden
facility: Department of Orthopaedic Surgery, Höglandssjukhuset District Hospital Eksjö
state: Region Jönköping County
Study officials:
affiliation: Department of Orthopaedic Surgery, Eksjö, Region Jönköping County and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
name: Björn A Alkner, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References: