Biology subjects

Baweja, H. S.

Publications and source records attributed to Baweja, H. S..

3 recordsLinked to original sources

bioRxiv2026

Acute molecular and chronic vastus lateralis adaptations to lengthened partial versus full range of motion resistance training in previously trained males

This study examined how lower-body lengthened partial (LP) versus full range of motion (FULL) resistance training affects acute post-exercise signaling, chronic hypertrophy, and cellular adaptations of the vastus lateralis (VL) muscle in resistance-trained men. Eight males (22{+/-}1 years old, 5.6{+/-}1.4 years training) completed a crossover study whereby VL biopsies were collected pre-exercise and 0, 3, and 24 hours following LP and FULL leg extension bouts for transcriptomic and anabolic signaling analyses (Experiment 1). Another 16 males (26{+/-}5 years old; 8.0{+/-}4.9 years training) completed an 8-week, twice-weekly lower-body intervention using a within-subject design (Experiment 2). One leg was assigned to FULL and the contralateral leg to LP training across three exercises (leg press, leg extension, and lying leg curl). Pre- and post-intervention outcomes included VL muscle cross-sectional area (mCSA) summed across five equidistant MRI-derived transverse slices and mid-thigh VL biopsy outcomes. As a secondary outcome, other hip and thigh muscles from Experiment 2 MRI scans were assessed. Condition x Time interactions for all outcomes were assessed using linear mixed-effects models. In Experiment 1, both conditions produced similar time-dependent changes in the VL transcriptome and anabolic (mTORC1 and Hippo) signaling, but minimal between-protocol interactions. In Experiment 2, VL summed mCSA significantly increased over time (mean change: 9.3 cm{superscript 2}, 95% CI [6.8, 11.8], P<0.001), but there was no clear evidence of differential change between protocols (LP-FULL change: -1.4 cm{superscript 2}, 95% CI [-6.1, 3.8], P=0.640). Additionally, no significant interactions existed for type I fiber CSA (P=0.476), type II fiber CSA (P=0.350), type I fiber myonuclei (P=0.813), type II fiber myonuclei (P=0.589), type I and II satellite cell number (P=0.102 and P=0.797, respectively), or total RNA content (P=0.537). Despite these null VL-centric findings, secondary Experiment 2 analyses provided some evidence that whole hamstring hypertrophy was greater following LP versus FULL (LP-FULL change: 3.9 cm{superscript 2}, 95% CI [-0.2, 7.9], P=0.058). In conclusion, 8 weeks of LP and FULL resistance training broadly elicit similar acute and chronic VL responses in previously trained men, though secondary hamstring findings suggest that differential responses may depend on exercises included in the resistance training program.

physiology↗

bioRxiv2024

Leg immobilization and subsequent recovery resistance training affect skeletal muscle angiogenesis related markers in young healthy adults regardless of prior resistance training experience

We recently reported that resistance trained (T, n=10) and untrained (UT, n=11) young adults experience vastus lateralis (VL) muscle atrophy following two weeks of disuse, and 8 weeks of recovery resistance training (RT) promotes VL hypertrophy in both participant cohorts. However, angiogenesis targets and muscle capillary number were not examined and currently no human studies that have sought to determine if disuse followed by recovery RT affects these outcomes. Thus, we examined whether disuse and/or recovery RT affected these outcomes. All participants underwent two weeks of left leg immobilization using locking leg braces and crutches followed by eight weeks (3d/week) of knee extensor focused progressive RT. VL biopsies were obtained at baseline (PRE), immediately after disuse (MID), and after RT (POST). Western blotting was used to assay angiogenesis markers and immunohistochemistry was performed in 16/21 participants to determine type I and II muscle fiber capillary number. Significant main effects of time (p<0.05) were observed for protein levels of VEGF (MID 0.100). Although disuse and recovery RT affect skeletal muscle angiogenesis-related protein targets, prior training history does not differentially affect these outcomes. NEW AND NOTEWORTHYThis is the first study to examine how limb immobilization and recovery resistance training affect molecular outcomes related to angiogenesis in younger adults with or without a prior training history. Regardless of resistance training history, the molecular responses are largely similar between participant cohorts and is suggestive of a reduced (pre-mid) and increased (mid-post) angiogenic response, with disuse and subsequent recovery resistance training.

physiology↗

bioRxiv2024

Effects of leg immobilization and recovery resistance training on skeletal muscle-molecular markers in previously resistance trained versus untrained adults

We sought to examine how resistance training (RT) status in young healthy individuals, either well-trained (T, n=10 (8 males)) or untrained (UT, n=11 (8 males)), affected muscle size and molecular markers with leg immobilization followed by recovery RT. All participants underwent two weeks of left leg immobilization via the use of crutches and a locking leg brace. After this two-week period, all participants underwent eight weeks (3 d/week) of knee extensor focused progressive RT. Vastus lateralis (VL) ultrasound-derived thickness and muscle cross-sectional area were measured at baseline (PRE), immediately after disuse (MID), and after RT (POST) with VL muscle biopsies collected at these time points. T and UT presented lower ultrasound derived VL size (cross-sectional area and thickness) values at MID versus PRE (p[≤]0.001), and values increased in both groups from MID to POST (p<0.05); however, VL size increased from PRE to POST in UT only (p<0.001). Mean and type II myofiber cross-sectional area (fCSA) values demonstrated a main effect of time where PRE and POST were greater than MID (p<0.05) and main effect of training status where T was greater than UT (P[≤]0.012). In both groups, satellite cell number was not affected by leg immobilization but increased in response to RT (p[≤]0.014), with T being greater than UT across all time points (p=0.004). Additionally, ribosome content (total RNA) decreased (p=0.010) from PRE to MID while the endoplasmic reticulum stress proteins (BiP, Xbp1s, and CHOP) increased from MID to POST regardless of training status. Finally, the phosphorylation states of mechanistic target of rapamycin complex-1 signaling proteins were not significantly altered for either group throughout the intervention. In conclusion, immobilization-induced muscle atrophy and recovery RT hypertrophy outcomes are similar between UT and T participants, and the lack of molecular signature differences between groups supports these findings. However, these data are limited to younger adults undergoing non-complicated disuse. Thus, further investigation to determine the impact of training status on prolonged leg immobilization models mirroring current medical protocols (e.g., following orthopedic injury and surgery) is warranted.

physiology↗