Potential Synergistic Effect of Combined Blood Flow Restriction Training and Betaine Supplementation on Skeletal Muscle

The purpose of the study is to determine whether there is a synergistic effect via combining both low-load blood flow restriction (BFR) training and betaine supplementation loading (6g/day for 14 days) on skeletal muscle anabolic signaling pathways that is mediated by enhancements in intracellular water. These effects are proposed to be greater than either BFR training or betaine supplementation alone or compared to control conditions (high-load non-occluded and/or placebo supplementation).

The purpose of the investigation is to determine whether the combination of blood flow restriction (BFR) training and betaine supplementation can synergistically augment phosphorylated targets associated with mechanotransduction and/or muscle protein synthesis relative to either modality alone and compared against control conditions (standard "high-intensity" resistance training and placebo supplementation) in healthy young males. Secondly, the investigators aim to determine if any potential synergistic effects are mediated by enhanced intracellular fluid volumes, as determined by the changes in water content between hydrated and dehydrated muscle samples, as well as through changes in both muscle and serum betaine concentrations. Finally, the investigators aim to assess differences in the aforementioned interventions on specific gene targets, the betaine/γ-aminobutyric acid transporter, myosin heavy chain I, IIa, and IIx lactate dehydrogenase A. Therefore, the specific aims of this study are to determine in healthy, young males: 1) whether combined BFR training and betaine supplementation significantly augment mechanotransductive growth-associated post-translational protein modifications via extra-to-intracellular fluid flux, alongside 2) potentially altered gene expression that otherwise characterizes phenotypical/biochemical changes in skeletal muscle.

The specific aims of the study are to determine whether:

1. The combination of BFR training and betaine supplementation demonstrates significantly greater phosphorylated FAK, ERK1/2, IRS1, and p70S6K, commensurate with greater wet-to-dry hydration changes, relative to any other combinations between BFR training, standard "high-load" training, betaine supplementation, and/or placebo ingestion.
2. The combination of BFR training and betaine supplementation will result in increased MYH2 gene expression, alongside decreases in MYH7 and MYH1 expression. Furthermore, this combination will also result in the highest degree of HIF-1 and Ldha, as well as the lowest BGT-1 gene expression relative to baseline levels.
3. The combination of BFR training and betaine supplementation will result in a higher load-volume accumulated relative to BFR-alone, and will not be statistically different than high-load-placebo training. Therein, the high-load-betaine group will have the greatest load-volume amidst any other combination of conditions.

Eligibility Criteria:
Inclusion Criteria:

* Only participants considered low risk for cardiovascular disease with no contraindications to exercise as outlined by the ACSM
* Have not consumed any nutritional supplements (aside from a multi-vitamin) one month prior to investigation
* Blood pressure \<140/90mmHg
* Resting heart rate \<90bpm-

Exclusion Criteria:

* sedentary individual as defined by the ACSM guidelines.
* inadequate resistance training experience (\<12 months, \<3x/week)
* vegetarian, vegan, or have dietary restrictions or supplements that potentially affect betaine metabolism.
* allergy to topical anesthetics.
* known metabolic or cardiovascular disorder including heart disease, arrhythmias, diabetes, thyroid disease, or hypogonadism.
* genetic disorders/polymorphisms that would act as direct contraindications to betaine supplementation (i.e. methyltetrahydrofolate reductase, hyperhomocysteinemia, etc.)
* bleeding disorder, history of pulmonary disease, hypertension, hepatorenal disease, musculoskeletal disorders, neuromuscular/ neurological diseases, autoimmune disease, cancer, peptic ulcers, anemia, or chronic infection (e.g., HIV).
* resting systolic/diastolic blood pressure and heart rate of more than 140/90 mmHg and 90, respectively.
* taking any blood thinning (e.g., warfarin, Jantoven, etc.), heart, pulmonary, thyroid, anti-hyperlipidemic, hypoglycemic, anti-hypertensive, endocrinologic (e.g, thyroid, insulin, etc), emotional/psychotropic (e.g., Prednisone, Ritalin, Adderall), or neuromuscular/neurological medications.
* taking anabolic androgenic steroids within the past year.