Biology subjects

Vann, C. G.

Publications and source records attributed to Vann, C. G..

4 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↗

bioRxiv2026

Regulation of Small RNAs by Exercise and Their Role in Insulin Sensitivity

We investigated effects of three aerobic exercise interventions, varying in amount and intensity with durations of 8-9-months on small RNA (smRNA) expression and regulatory pathways in skeletal muscle and plasma from 120 participants. Using untargeted smRNA sequencing focused on miRNAs and piRNAs, adjusting for demographics and bodyweight, we identified 124 muscle smRNAs altered by exercise amount and 15 by intensity, and 47 plasma smRNAs altered by intensity and one by amount. These smRNAs were enriched in metabolic, transcriptional, translational, and cell cycle pathways. Exercise-induced changes in several smRNAs-six from muscle and five from plasma-and exercise-induced reduction in body weight, aligned with improvement in insulin sensitivity (p<0.05). These findings demonstrate tissue-specific regulation of smRNAs by exercise and identify potential candidates for exercise mimetics to modulate muscle insulin sensitivity.

physiology↗

bioRxiv2025

Skeletal muscle mitochondrial responses to a single bout and six weeks of high load versus high volume resistance training in previously trained men

The effects of higher-load (HL) versus higher-volume (HV) resistance training (RT) on various molecular outcomes are similar. However, mitochondrial responses remain understudied. Therefore, the purpose of this study was to interrogate mitochondrial mRNA and protein responses to acute and chronic HL versus HV RT. Vastus lateralis biopsies from resistance trained males in two prior studies were assessed. In STUDY 1, 11 college-aged men completed an acute bout of either HL or HV RT exercises to failure. Biopsies were collected at PRE, 3 hours post-, and 6 hours post-exercise. In STUDY 2, 15 college-aged men participated in six weeks of supervised unilateral RT where each leg was assigned to either HL or HV RT. Biopsies were collected from both legs prior to and 72 hours following last training bout of the intervention. Biopsies from both studies were used to assess mitochondrial mRNAs, and STUDY 2 biopsies were assayed for mitochondrial proteins and CS activity. Results from both studies revealed several significant main effects of time but no significant interactions. Additionally, CS activity, a surrogate of mitochondrial content, decreased following chronic RT (p=0.016) but no interaction was observed between the HV and HL leg over time (p=0.882). In conclusion, while RT resulted in both acute mitochondrial mRNA as well as chronic CS activity and mitochondrial protein responses, there were no differences in the HL versus HV paradigms on these outcomes.

physiology↗

bioRxiv2021

Resistance training rejuvenates the mitochondrial methylome in aged human skeletal muscle

Resistance training (RT) alters skeletal muscle nuclear DNA methylation patterns (or the methylome). However, no study has examined if RT affects the mitochondrial DNA (mtDNA) methylome. Herein, ten older untrained males (65{+/-}7 years old) performed six weeks of full-body RT (twice weekly). Body composition and knee extensor torque were assessed prior to and 72 hours following the last RT session. Vastus lateralis (VL) biopsies were also obtained. VL DNA was subjected to reduced representation bisulfite sequencing providing excellent coverage across the ~16-kilobase mtDNA methylome (254 CpG sites). Various biochemical assays were also performed, and older male data were compared to younger trained males (22{+/-}2 years old, n=7). RT increased whole-body lean tissue mass (p=0.017), VL thickness (p=0.012), and knee extensor torque (p=0.029) in older males. RT also profoundly affected the mtDNA methylome in older males, as 63% (159/254) of the CpG sites demonstrated reduced methylation (p<0.05). Notably, several mtDNA sites presented a more "youthful" signature after RT in older males when comparisons were made to younger males. The 1.12 kilobase D-loop/control region on mtDNA, which regulates mtDNA replication and transcription, possessed enriched hypomethylation in older males following RT. Enhanced expression of mitochondrial H- and L-strand genes and increases in mitochondrial complex III and IV protein levels were also observed (p<0.05). This is the first study to show RT alters the mtDNA methylome in skeletal muscle. Observed methylome alterations may enhance mitochondrial transcription, and RT remarkably evokes mitochondrial methylome profiles to mimic a more youthful signature in older males.

molecular biology↗