Core Strength Training in Youth
Condition: Exercise; Strength Training
Study type: Interventional

Summary: 
      Background: It has been demonstrated that core strength training is an effective means to
      enhance trunk muscle strength (TMS) and athletic performance in youth. However, the role of
      instability with core strength training is unresolved in youth. This study specifically will
      investigate the effects of core stability (CST) compared to core instability strength
      training (CIST) on physical fitness in adolescents.

      Methods: Twenty-seven (14 girls, 13 boys) healthy adolescents (age 14±1 years) will be
      assigned to a CST (n=13) or a CIST (n=14) group. Both training programs will last 6 weeks (2
      sessions/week) and included frontal, dorsal, and lateral core exercises. During CIST, these
      exercises will be conducted on unstable surfaces (e.g., TOGU© DYNAIR CUSSIONS, THERA-BAND©
      STABILITY TRAINER).

      Expected Results: Based on selected results reported in the literature, we hypothesize that
      participants performing CIST as compared to CST will show larger improvements in physical
      fitness tests (i.e., strength, speed, flexibility, coordination, balance) following training.
      Of note, training induced gains in strength, speed, flexibility, coordination, and balance
      are of vital importance for sports performance, everyday activities, and injury prevention.
    

Detailed description: 
      Adaptations following core strength training performed on stable (CST) as compared to
      unstable surface conditions (CIST) will be assessed in a pre- versus post-test design. The
      training period will last 6 weeks to induce training induced changes in measures of strength,
      speed, flexibility, coordination, and balance. These health (i.e., strength, flexibility) and
      skill-related (i.e., balance, coordination, speed) components of physical fitness will be
      assessed using physical fitness tests (i.e., Bourban TMS test, standing long jump test, 20-m
      sprint test, stand-and-reach test, jumping sideways test, Emery balance test, Y balance
      test).

      Twenty-seven healthy adolescent boys and girls will participate in this study after the
      experimental procedures were explained. An a priori power analysis with an assumed Type I
      error of 0.05 and a Type II error rate of 0.20 (80% statistical power) was calculated for
      measures of trunk muscle strength and revealed that 13 participants per group would be 105
      sufficient to observe medium Test x Group interaction effects. Study participants will be
      recruited from local sports clubs.

      Both core strength training programs will be supervised and conducted by 2 experienced
      physiotherapists. The two programs will be organized as circuit training with each instructor
      supervising 6-7 participants. Both training programs will comprise 2 training sessions per
      week with a total of 12 training sessions for each intervention group. Each training session
      will last 30 min, starting with a brief warm-up program mainly consisting of core strength
      exercises at moderate intensities and ending with a cool-down program (i.e., dynamic
      stretching). During the main part of training, both groups mainly conduct the "big 3"
      exercises as described by McGill. These include the curl-up, side bridge, and quadruped
      position. In other words, every single training session will consist of frontal, dorsal, and
      lateral core exercises. The only difference between the 2 intervention groups is that the
      CIST protocol comprised core exercises that will be conducted on unstable elements (e.g.,
      TOGU© DYNAIR PRO, SENSO, TOGU© REDONDO BALLS, TOGU© POWERBALLS, THERA-BAND© STABILITY
      TRAINER, THERA-BAND© EXERCISE BALL), whereas the CST program will contain the same exercises
      on stable surface only.

      Prior to testing, all participants will perform a standardized 5-minutes warm-up which
      consists of bipedal and monopedal balance, submaximal plyometric, and skipping exercises.
      Thereafter, physical fitness tests (i.e., Emery balance test, Y balance test, stand-and-reach
      test, 20-m sprint test, jumping sideways test, standing long jump test, Bourban TMS test)
      will be assessed.

      A multivariate analysis of variance (MANOVA) will be used to detect differences between study
      groups in all baseline variables. The effects of core strength training on variables of
      physical fitness will be analysed in separate 2 (Group: CST, CIST) x 2 (Test: pre, post)
      ANOVA with repeated measures on test. When Test x Group interactions reached the level of
      significance, group-specific post hoc tests (i.e., paired t-tests) will be conducted to
      identify the comparisons that were statistically significant. Additionally, the
      classification of effect sizes (f) will be determined by calculating partial eta squared.
    

Intervention name(s): core strength training
Intervention type(s): Behavioral
Intervention description(s): Both training programs will last 6 weeks and comprise 2 training sessions per week with a total of 12 training sessions for each intervention group. Each training session will last 30 min, starting with a brief warm-up program mainly consisting of core strength exercises at moderate intensities and ending with a cool-down program (i.e., dynamic stretching). During the main part of training, both groups mainly conduct the "big 3" exercises as described by McGill. These will include the curl-up, side bridge, and quadruped position. In other words, every single training session will consist of frontal, dorsal, and lateral core exercises. The only difference between the 2 intervention groups is that the CSTU protocol comprise core exercises that will be conducted on unstable elements (e.g., TOGU© DYNAIR PRO, THERA-BAND© STABILITY TRAINER), whereas the CSTS program will contain the same exercises on stable surface only.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: resistance training; trunk muscle strength; physical fitness; adolescent