Abstract

Strength adaptations from short-term resistance training are thought to be related primarily to neurological adaptations. Considering brain-derived neurotrophic factor (BDNF) role in the nervous system, it is possible that BDNF has a role in these adaptations. Fourteen untrained males were randomized into either a resistance training (RT; n =8) or control (CON; n=6) group. Motor unit (MU) recruitment at 50% and 80% of each participant's maximal voluntary isometric contraction (MVIC), muscle cross sectional area (CSA) and thickness (MT), as well as one-repetition maximum (1RM) of the squat (SQT), leg press (LP), and leg extension (LE) were performed before (PRE) and after (POST) the training period. Following the MU assessment, the recruitment threshold (RT; % MVIC) and mean firing rate (MFR; pulse per second [pps]) of each MU were determined. Linear regression was used to quantify the slope (pps/% MVIC) and y-intercept (pps) of the MFR versus RT relationship for each participant and time point. Participants completed an acute resistance exercise bout at PRE and POST consisting of 3 sets of 8 – 10 repetitions with 90 seconds of rest between each set of SQT, LP, and LE. Blood samples were obtained following a 4-hour fast before (BL), immediately-(IP), and one-(1H) hour post resistance exercise. RT subjects performed the same resistance exercise protocol at PRE twice a week for 3-weeks. CON subjects were instructed to not perform any resistance exercise. Area under the curve (AUC) analysis was determined by the trapezoidal method. Pearson product-moment correlations were used to examine selected bivariate relationships. The ΔBDNF AUC was significantly correlated to the relative 80% Δy-intercept (r=-0.626, p=0.030), and trended to be correlated to the relative 80% Δslope (r=0.551, p=0.063). Our results indicate that Δ in plasma BDNF concentrations appear to be related to Δ's MU recruitment at high intensities (80% of MVIC) of exercise.

Notes

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Graduation Date

2018

Semester

Spring

Advisor

Hoffman, Jay

Degree

Doctor of Philosophy (Ph.D.)

College

College of Education and Human Performance

Degree Program

Education; Exercise Physiology

Format

application/pdf

Identifier

CFE0006988

URL

http://purl.fcla.edu/fcla/etd/CFE0006988

Language

English

Release Date

May 2019

Length of Campus-only Access

1 year

Access Status

Doctoral Dissertation (Campus-only Access)

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