Why do People Respond Differently to Resistance Training? — PreEx  

Resistance Training Clinical Trial

Official title: Precision Exercise (PreEx): Identifying the Determinants of Inter-individual Variation in Resistance Training Responses

Status Recruiting

Clinical Trial Summary

It is well known that regular resistance training (RT) can have health benefits. However, considerable heterogeneity in RT responses has been observed. The mechanisms underlying an individual's ability to respond to RT are mainly unknown but involve a complex network of genomic and non-genomic factors. The investigators aim to examine heterogeneity in physiological responses to RT while closely monitoring other environmental factors (e.g., physical activity levels, nutrition, sleep, and stress). Participants are healthy sedentary men and women aged 18-45 (n=240). A controlled 12-week RT intervention will be conducted to characterize RT response. Data will be collected before, during, and after the study period by using measurements of body composition, muscle size, and physical fitness characteristics, as well as by collecting blood samples and questionnaires. The investigators will identify the underlying factors contributing to why people differ in their physiological responses to RT. For this, comprehensive background data will be collected to identify common denominators underlying individual differences in response to RT. The investigators will use sophisticated analytical methods to reveal new predictors of training response for different traits. This research project aims to gain insight into the sources of individual variation in physiological responses to RT. On this basis, exercise training can be personalized to optimize the benefits of RT for all individuals. Ultimately, the investigators will also be able to justify better using RT as part of individualized healthcare strategies in the future.

Clinical Trial Description

The benefits of regular resistance training (RT) are well known, but it is also well known that tremendous inter-individual variability can be detected in responses to RT. The reason(s) for individual variations in responses to RT is a very complex physiological phenomenon and is still poorly known. The individual variation in trainability suggests genetic diversity but non-genetic determinants potentially contribute significantly to training responses. The investigators hypothesize that in this study, a broad spectrum of adaptive responses to RT is detected. By scrutinizing participants' backgrounds, it can be elucidated why individuals respond differently to regular RT. Furthermore, it is hypothesized that the investigators can identify specific predictive markers for RT responsiveness. That is possible by combining information on training responsiveness with the personal characteristics of the participant. Healthy young adults will be recruited to the study to understand the biological basis of heterogeneity in exercise responses by minimizing potential age and health-related physiological confounders. They are premised to respond positively to the study's primary outcome, which is maximal lower limb muscle strength. To collect comprehensive data, the number of participants is maximized within practical limitations, and thus, 240 participants are recruited. According to the investigators' extensive experience in fully supervised exercise training interventions with comprehensive and time-consuming physiological measures, this is the maximum number of participants that can examine within the timeframe allocated for data collection. Participants comprise an equal proportion of men and women, and sex differences in RT responsiveness will be investigated as a secondary aim of the study. The study design is a single-arm trial. After assessing eligibility, participants engage in the baseline measurements and the 12-week fully supervised RT intervention. The training protocol is identical for each participant. The participants will train two times weekly, and the program will target all major muscle groups. Each training session includes exercises for the lower (leg presses, knee extensions/flexions) and upper body (bench presses, biceps curls, and seated row). For the first two weeks, the participants will perform ~15 repetitions per set (approximately 50-70% of the one repetition maximum, 1RM) and three sets per exercise. After that, the training load will be at an 8- to 12-RM zone for four sets per exercise. The change in muscle strength (10RM test) is assessed in the gym at 2-week intervals. Loads are increased progressively for the next 2-week period if the prescribed number of repetitions is completed for a given load. A questionnaire on perceived exertion in each exercise session (sRPE) will be obtained to evaluate the participant's intrinsic effort in performing exercises. The training is executed in a local university gym with a standardized time of day, and training diaries are used to track the training loads. The measurements are obtained at baseline and after the intervention. Participants are informed of the study goals and are carefully familiarized with study protocols. All the tests are carried out at the same time of day. The participants are given feedback on their test results during the project. The primary outcome of this study is maximum leg press strength. Gains in muscle strength are determined by increased muscle size and/or improvements in capability to activate working muscles. In addition to genetics, environmental factors are essential in explaining individuality in training responses. In this project, the investigators focus on gathering comprehensive data on variables of participants' background, nutrition, health status, and physical activity that can potentially influence the heterogeneity of RT adaptations. ;

Related Conditions & MeSH terms

• Resistance Training

• NCT number: NCT05874986
• Study type: Interventional
• Source: University of Jyvaskyla
• Contact: Juha P Ahtiainen, Assoc.Prof.
• Phone: +358408053740
• Email: juha.ahtiainen@jyu.fi
• Status: Recruiting
• Phase: N/A
• Start date: February 22, 2023
• Completion date: August 30, 2024