RESISTANCE-TRAINED INDIVIDUALS EXPERIENCE GREATER ATROPHY STRENGTH LOSS DURING LEG IMMOBILIZATION VERSUS UNTRAINED INDIVIDUALS

Authors

Derick A. Anglin, Auburn UniversityFollow
J. Max Michel, Auburn UniversityFollow
Mason C. McIntosh, Auburn UniversityFollow
Daniel L. Plotkin, Auburn UniversityFollow
Joshua S. Godwin, Auburn UniversityFollow
Phillip J. Agostinelli, Auburn UniversityFollow
Madison L. Mattingly, Auburn UniversityFollow
Nicholas J. Kontos, Auburn UniversityFollow
Alexander C. Berry, Auburn UniversityFollow
Marina M. Vega, Auburn UniversityFollow
Darren T. Beck, Auburn UniversityFollow
C. Brooks Mobley, Auburn UniversityFollow
Matt S. Stock, University of Central FloridaFollow
Harsimran S. Baweja, Auburn UniversityFollow
Michael D. RobertsFollow

Abstract

BACKGROUND: Skeletal muscle is a highly plastic tissue that responds to stimuli such as mechanical overload/resistance training (RT) or disuse/unloading. It has been demonstrated that individuals who perform RT, undergo detraining, and then re-engage in RT experience more skeletal muscle hypertrophy upon retraining than on the initial block of RT despite returning to baseline size with detraining. What is not known, however, is whether training status affects the progression of disuse-induced atrophy. Therefore, the purpose of this study was to examine the effects of 2-weeks of lower limb immobilization on lower body strength and vastus lateralis (VL) thickness in a cohort of young, healthy previously trained (T) or training naïve (UT) men and women. METHODS: In this study, 21 young healthy men and women (n=10 T; n=11 UT) underwent 2-weeks of left leg immobilization via a locking leg brace and crutches. Data were collected at baseline (PRE), and after the 2-week immobilization period (POST). Muscle thickness was assessed via ultrasound of the VL, while lower limb strength was determined via three repetition maximums (3RMs) of the hex bar deadlift and the seated leg press. Data were checked for normality by a Shapiro-Wilk test and analyzed via two-way ANOVAs to compare lower body strength and VL thickness pre- and post-immobilization. RESULTS: A two-way ANOVA for hex bar deadlift 3 RMs did not show a training status x time interaction (P=0.566), but did reveal main effects of training status and time (P<0.005) with T being greater than UT at both time points (P<0.001) and T decreasing from PRE to POST (P<0.034). A two-way ANOVA for leg press 3RMs showed a significant interaction, along with main effects of training status and time (P<0.008) with T being greater than UT at PRE and POST (P<0.001) and only T decreasing from PRE to POST (P=0.001). VL thickness also showed a significant interaction, along with main effects of training status and time (P≤0.044) with only T decreasing from PRE to POST (P<0.001) and T being greater than UT only at PRE (P=0.014). CONCLUSIONS: Trained individuals demonstrate greater losses in muscular strength and VL thickness compared to untrained individuals after 2 weeks of leg immobilization, and mechanistic research is warranted.

Recommended Citation

Anglin, Derick A.; Michel, J. Max; McIntosh, Mason C.; Plotkin, Daniel L.; Godwin, Joshua S.; Agostinelli, Phillip J.; Mattingly, Madison L.; Kontos, Nicholas J.; Berry, Alexander C.; Vega, Marina M.; Beck, Darren T.; Mobley, C. Brooks; Stock, Matt S.; Baweja, Harsimran S.; and Roberts, Michael D. (2024) "RESISTANCE-TRAINED INDIVIDUALS EXPERIENCE GREATER ATROPHY STRENGTH LOSS DURING LEG IMMOBILIZATION VERSUS UNTRAINED INDIVIDUALS," International Journal of Exercise Science: Conference Proceedings: Vol. 16: Iss. 3, Article 269.
Available at: https://digitalcommons.wku.edu/ijesab/vol16/iss3/269