Effects of Resistance Training Overload Progression Protocols on Strength and Muscle Mass.

The aim of this study was to compare the effects of progressive overload in resistance training on muscle strength and cross-sectional area (CSA) by specifically comparing the impact of increasing load (LOADprog) versus an increase in repetitions (REPSprog). We used a within-subject experimental design in which 39 previously untrained young persons (20 men and 19 women) had their legs randomized to LOADprog and REPSprog. Outcomes were assessed before and after 10 weeks of training. Muscle strength was assessed using the one repetition maximum (1RM) test on the leg extension exercise, and the CSA of the vastus lateralis was assessed by ultrasonography. Both protocols increased 1RM values from pre (LOADprog: 52.90±16.32 kg; REPSprog: 51.67±15.84 kg) to post (LOADprog: 69.05±18.55 kg, REPSprog: 66.82±17.95 kg), with no difference between them (P+>+0.05). Similarly, both protocols also increased in CSA values from pre (LOADprog: 21.34±4.71 cm²; REPSprog: 21.08±4.62 cm²) to post (LOADprog: 23.53±5.41 cm², REPSprog: 23.39±5.19 cm²), with no difference between them (P+>+0.05). In conclusion, our findings indicate that the progression of overload through load or repetitions can be used to promote gains in strength and muscle hypertrophy in young men and women in the early stages of training.

Application of Artificial Intelligence to Automate the Reconstruction of Muscle Cross-Sectional Area Obtained by Ultrasound.

PURPOSE: Manual reconstruction (MR) of the vastus lateralis (VL) muscle cross sectional area (CSA) from sequential ultrasound (US) images is accessible, reproducible and has concurrent validity with magnetic resonance imaging. However, this technique requires numerous controls and procedures during image acquisition and reconstruction, making it laborious and time-consuming. The aim of this study was to determine the concurrent validity of VL CSA assessments between MR and computer vision-based automatic reconstruction (AR) of CSA from sequential images of the VL obtained by US. METHODS: The images from each sequence were manually rotated to align the fascia between images and thus visualize the VL CSA. For the AR, an artificial neural network model was utilized to segment areas of interest in the image, such as skin, fascia, deep aponeurosis, and femur. This segmentation was crucial to impose necessary constraints for the main assembly phase. At this stage, an image registration application, combined with differential evolution, was employed to achieve appropriate adjustments between the images. Next, the VL CSA obtained from the MR (n = 488) and AR (n = 488) techniques were used to determine their concurrent validity. RESULTS: Our findings demonstrated a low coefficient of variation (CV) (1.51%) for AR compared to MR. The Bland-Altman plot showed low bias and close limits of agreement (+1.18 cm2, -1.19 cm2), containing more than 95% of the data points. CONCLUSIONS: The AR technique is valid compared to MR when measuring VL CSA in a heterogeneous sample.

Resistance Training With Partial Blood Flow Restriction in a 99-Year-Old Individual: A Case Report.

In aging populations for which the use of high loads is contraindicated, low load resistance training associated with blood flow restriction (RT-BFR) is an alternative strategy to induce muscle mass gains. This study investigates the effects of RT-BFR on muscle mass, muscle function, and quality of life of a 99-year-old patient with knee osteoarthritis and advanced muscle mass deterioration. Training protocol consisted of 24 sessions of a unilateral free-weight knee extension exercise associated with partial blood flow restriction through a manometer cuff set at 50% of complete vascular occlusion pressure. We evaluated: cross-sectional area (CSA) and thickness (MT) of the vastus lateralis muscle by ultrasound; function through the Timed Up and Go (TUG) test; and quality of life (QoL) by the WHOQOL-bref, WHOQOL-OLD and WOMAC questionnaires. All tests were performed prior to the training period (Pre) and after the 12th (Mid) and 24th (Post) sessions. Changes were considered significant if higher than 2 times the measurement's coefficient of variation (CV). After 24 sessions, there was an increase of 12% in CSA and 8% in MT. Questionnaires scores and TUG values worsened from Pre to Mid and returned in Post. We consider RT-BFR a viable and effective strategy to promote muscle mass gains in nonagenarians and delay the decline in functionality and QoL associated with aging.