βA is a non-proteinogenic amino acid that is synthesized in the liver as the final metabolite of uracil and thymine degradation. While produced endogenously, the primary source of βA in humans comes from their diet. Meat is the primary source of dietary βA, with highest concentrations found in chicken and turkey [11]. The performance enhancing potential of βA supplementation lies in its effect on increasing muscle carnosine levels [4, 7, 8, 12] due to its role as the limiting factor in the muscle carnosine synthesis [12–14]. Carnosine (β-alanyl-L-histidine) is a dipeptide found in muscle tissue that acts as an intramuscular buffer of [H+] [4, 7, 8, 12]. During high intensity exercise, a greater reliance
on the glycolysis and phosphagen systems to supply ATP to working muscles results in an accumulation of [H+] which leads to exercise-induced metabolic acidosis [15]. A decline in pH has been implicated as BIBW2992 a cause of muscle fatigue and decreased muscle contractile function [16]. Attenuating exercise induced acidosis is purported to result in performance improvements in activities www.selleckchem.com/products/pd-1-pd-l1-inhibitor-2.html requiring prolonged bouts of high intensity work. This is supported by findings that muscle carnosine concentrations are higher in sprinters [17], bodybuilders [18], and team sport
athletes regularly participating in high intensity intermittent exercise [19, 20] than in their sedentary counterparts. Previous studies investigating Rabusertib the effect of βA on performance measures have shown improvements in total work done (TWD) [4, 10], time to exhaustion (TTE) [1, 4, 10], physical working capacity at fatigue threshold (PWCFT) [1, 3], power output at lactate threshold (LT) [5], attenuated fatigue during repeated bouts of resistance training [7], and final 30 second sprint performance during a 2 hour time trial [9]. Research has however been conducted using primarily cycle ergometry
[1–5, 9, Lck 10], so it remains to be determined if βA supplementation would have an ergogenic effect during running performance. Therefore, we hypothesized that βA supplementation would delay OBLA. Therefore, the purpose of this study was to determine the effects of 4 weeks of βA supplementation on HR@OBLA, %HRmax@OBLA, %VO2max@OBLA, VO2max during incremental treadmill running. Methods Subjects Seventeen men who were recreationally active and running at least 3 times per week and had not taken any sports supplements for at least 6 weeks volunteered to participate in this study (Table 1). Subjects provided signed consent to participate and all study procedures were approved by the Northern Illinois University Institutional review board prior to enrollment in the study. Table 1 Physical Characteristics of Subjects. Variable βA (n = 8) PL (n = 9) Age (yr) 24.9 ± 5.1 24.9 ± 4.3 Height (cm) 181.4 ± 9.9 179.8 ± 7.9 Body Mass (kg) 77.9 ± 9.0 80.6 ± 9.1 BMI 23.7 ± 2.3 24.9 ± 1.