A Study of Race Pacing in the Running Leg of the Japan University Triathlon Championship.

Choosing an appropriate pacing strategy is important for good triathlon performance. In the Japan Student Triathlon Championship held in 2020, the men's category was divided into two groups, which was a different racing style from the previous races that all athletes start at the same time. It is highly likely that the performance level will vary as grouping was performed according to the competence of each player. The aim of this study was to understand the relationship of the total time and time of each leg between the superior performance group and the inferior performance group, as well as the difference in pacing during running in participants of the 2020 Japan University Triathlon Championship Watarase Competition, which was held under unconventional conditions. We analyzed 153 male athletes (Group A: 77; Group B: 76) who completed the race. The total race time, leg time, and average speed in each leg and its variation coefficient were evaluated based on the official results of the competition and footage recorded during the race. The results showed that the total time and leg time for each leg were significantly shorter in Group A compared to those in Group B (p < 0.05). In both groups, the Lap 4 run was significantly slower than those of Laps 1-3 (p < 0.05), while there was no significant difference in the running speed to average speed ratio across all laps between the groups (p < 0.05). Thus, there was a difference in running speed between the groups, but no significant difference in pacing. The results of this study serve as basic data for examining superior pacing strategies, although further studies on a wide range of competition levels are necessary.

Taurine supplementation enhances endurance capacity by delaying blood glucose decline during prolonged exercise in rats.

Taurine enhances physical performance; however, the underlying mechanism remains unclear. This study examined the effect of taurine on the overtime dynamics of blood glucose concentration (BGC) during endurance exercise in rats. Male F344 rats were subjected to transient treadmill exercise until exhaustion following 3 weeks of taurine supplementation or non-supplementation (TAU and CON groups). Every 10 min during exercise, BGC was measured in blood collected through cannulation of the jugular vein. Gluconeogenesis-, lipolysis-, and fatty acid oxidation-related factors in the plasma, liver, and skeletal muscles were also analyzed after 120-min run. Exercise time to exhaustion was significantly longer with taurine supplementation. BGC in the two groups significantly increased by 40 min and gradually and significantly decreased toward the respective exhaustion point. The decline in BGC from the peak at 40 min was significantly slower in the TAU group. The time when the once-increased BGC regressed to the 0-time level was significantly and positively correlated with exercise time until exhaustion. At the 120-min point, where the difference in BGC between the two groups was most significant, plasma free fatty acid concentration and acetyl-carnitine and N-acetyltaurine concentrations in skeletal muscle were significantly higher in the TAU group, whereas glycogen and glucogenic amino acid concentrations and G6Pase activity in the liver were not different between the two groups. Taurine supplementation enhances endurance capacity by delaying the decrease in BGC toward exhaustion through increases of lipolysis in adipose tissues and fatty acid oxidation in skeletal muscles during endurance exercise.

N-acetyltaurine and Acetylcarnitine Production for the Mitochondrial Acetyl-CoA Regulation in Skeletal Muscles during Endurance Exercises.

During endurance exercises, a large amount of mitochondrial acetyl-CoA is produced in skeletal muscles from lipids, and the excess acetyl-CoA suppresses the metabolic flux from glycolysis to the TCA cycle. This study evaluated the hypothesis that taurine and carnitine act as a buffer of the acetyl moiety of mitochondrial acetyl-CoA derived from the short- and long-chain fatty acids of skeletal muscles during endurance exercises. In human subjects, the serum concentrations of acetylated forms of taurine (NAT) and carnitine (ACT), which are the metabolites of acetyl-CoA buffering, significantly increased after a full marathon. In the culture medium of primary human skeletal muscle cells, NAT and ACT concentrations significantly increased when they were cultured with taurine and acetate or with carnitine and palmitic acid, respectively. The increase in the mitochondrial acetyl-CoA/free CoA ratio induced by acetate and palmitic acid was suppressed by taurine and carnitine, respectively. Elevations of NAT and ACT in the blood of humans during endurance exercises might serve the buffering of the acetyl-moiety in mitochondria by taurine and carnitine, respectively. The results suggest that blood levels of NAT and ACT indicate energy production status from fatty acids in the skeletal muscles of humans undergoing endurance exercise.

Exercise Intensity during Olympic-Distance Triathlon in Well-Trained Age-Group Athletes: An Observational Study.

The aim of this study was to examine the exercise intensity during the swimming, cycling, and running legs of nondraft legal, Olympic-distance triathlons in well-trained, age-group triathletes. Seventeen male triathletes completed incremental swimming, cycling, and running tests to exhaustion. Heart rate (HR) and workload corresponding to aerobic and anaerobic thresholds, maximal workloads, and maximal HR (HRmax) in each exercise mode were analyzed. HR and workload were monitored throughout the race. The intensity distributions in three HR zones for each discipline and five workload zones in cycling and running were quantified. The subjects were then assigned to a fast or slow group based on the total race time (range, 2 h 07 min-2 h 41 min). The mean percentages of HRmax in the swimming, cycling, and running legs were 89.8% ± 3.7%, 91.1% ± 4.4%, and 90.7% ± 5.1%, respectively, for all participants. The mean percentage of HRmax and intensity distributions during the swimming and cycling legs were similar between groups. In the running leg, the faster group spent relatively more time above HR at anaerobic threshold (AnT) and between workload at AnT and maximal workload. In conclusion, well-trained male triathletes performed at very high intensity throughout a nondraft legal, Olympic-distance triathlon race, and sustaining higher intensity during running might play a role in the success of these athletes.

Relationship between early-onset muscle soreness and indirect muscle damage markers and their dynamics after a full marathon.

BACKGROUND/OBJECTIVE: Muscle soreness and damage occurs after completing a full marathon. Here we refer to muscle soreness induced by prolonged running as early-onset muscle soreness (EOMS) because muscle soreness and damage markers induced after prolonged running are different from delayed-onset muscle soreness (DOMS) and muscle damage markers induced after eccentric contraction, such as resistance exercise. The dynamics and relationship between muscle damage markers and EOMS are unclear; therefore, in this study, we aimed to elucidate the relationship between EOMS and indirect muscle damage markers, and their dynamics after a full marathon. METHODS: The following measurements were performed in 19 subjects who completed a full marathon: perceived muscle soreness (using a numeric rating scale), thigh circumference (CIR), hip joint range of motion (ROM), jump height (JH) and muscle damage marker activities in the blood (CK, AST, LDH, ALD) before (Pre), after (Post) and every day for 4 days after a full marathon (D1-4). RESULTS: EOMS was induced, as determined by the numeric rating scale score peaking immediately after a full marathon. ROM and JH significantly decreased and all muscle damage markers significantly increased after a full marathon. Serum CK and AST peaked at D1. Serum LDH and ALD peaked at Post and D3. Each marker showed different dynamics. CIR significantly decreased after a full marathon. CONCLUSION: Muscle soreness peaked and muscle damage markers in the blood showed different dynamics after a full marathon. In other words, this is different from DOMS.

LDH isoenzyme 5 is an index of early onset muscle soreness during prolonged running.

BACKGROUND: Muscle soreness is also induced during prolonged running such as a full marathon, and muscle soreness and increased damage markers are detected immediately after such a running. We named this muscle soreness, early onset muscle soreness (EOMS). Additionally, lactate dehydrogenase (LDH) level which has some isoenzyme is increased immediately after prolonged exercise. However, it is unclear that EOMS is related to muscle damage markers on prolonged running. This study aimed to determine at which point EOMS, and muscle damage markers are related to EOMS during prolonged running. METHODS: We studied 11 male subjects who habitually perform aerobic exercise. They ran 30 km at 90% of ventilatory threshold intensity. Every 10 km, we estimated perceived muscle soreness, and sampled blood to measure muscle and liver damage, inflammation, and oxidative stress (d-ROM and BAP) markers. RESULTS: Muscle soreness score lower limbs were significantly appeared at 20 km compared to that at 0 km. Serum lactate dehydrogenase (LDH) level increased at 30 km compared to that at 0 km. LDH isoenzymes 3, 4, and 5, and neutrophils significantly increased at 30 km compared to those at 0 km. Serum LDH isoenzyme 5 and change in aspartate aminotransferase significantly increased at 20 km. In addition, there was a significant correlation between the thigh NRS and amount of serum LDH isoenzyme 5 from 0 km to 20 km. d-ROM and BAP increased at 10 km compared to those at 0 km. CONCLUSIONS: EOMS started to occur at 20 km during a 30 km running task. Our data suggest that LDH isoenzyme 5 is a marker of occurrence in EOMS during prolonged running.

Effect of BCAA supplement timing on exercise-induced muscle soreness and damage: a pilot placebo-controlled double-blind study.

BACKGROUND: The aim of the present study was to compare the effects of branched-chain amino acid (BCAA) supplementation taken before or after exercise on delayed onset muscle soreness (DOMS) and exercise-induced muscle damage (EIMD). METHODS: Fifteen young men (aged 21.5±0.4 years) were given either BCAA (9.6 g·day-1) or placebo before and after exercise (and for 3 days prior to and following the exercise day) in three independent groups: the control group (placebo before and after exercise), the PRE group (BCAA before exercise and placebo after exercise), and the POST group (placebo before exercise and BCAA after exercise). Participants performed 30 repetitions of eccentric exercise with the non-dominant arm. DOMS, upper arm circumference (CIR), elbow range of motion (ROM), serum creatine kinase (CK), lactate dehydrogenase (LDH), and aldolase, BCAA, and ß-hydroxy-ß-methylbutyrate (3HMB) were measured immediately before and after the exercise and on the following 4 days. RESULTS: Serum BCAA and 3HMB concentrations increased significantly in the PRE group immediately after the exercise, recovering to baseline over the following days. In the days following the exercise day, DOMS, CIR, and ROM were significantly improved in the PRE group compared to the control group, with weaker effects in the POST group. Serum activities of CK, LDH, and aldolase in the days following the exercise day were significantly suppressed in the PRE group compared to control group. CONCLUSIONS: The present study confirmed that repeated BCAA supplementation before exercise had a more beneficial effect in attenuating DOMS and EIMD induced by eccentric exercise than repeated supplementation after exercise.

Increased N-Acetyltaurine in the Skeletal Muscle After Endurance Exercise in Rat.

Taurine is metabolized to a novel metabolite, N-acetyltaurine (NAT), through N-acetylation with acetate. Furthermore, NAT production increases when the endogenous production of acetate is elevated in some situations, such as alcohol catabolism and endurance exercise. We have previously reported that both the serum concentration and urinary excretion of NAT from humans were increased after endurance exercise, and that NAT was secreted by cultured skeletal muscle cells exposed to both acetate and taurine. The present study evaluated the hypothesis that NAT is synthesized in the skeletal muscle after endurance exercise. Normal rats were loaded to a transient treadmill running until exhaustion. Serum, skeletal muscle, and liver were collected immediately after the exercise. The NAT concentration in the plasma and in the soleus muscle from the exercised rats was significantly increased compared to that in the samples from the sedentary control rats. There was a significant positive correlation in the NAT concentration between the plasma and soleus muscle. The NAT concentration in the liver was unchanged after the endurance exercise. These results confirm that the significantly increased NAT in both the serum and urine after endurance exercise is derived from NAT synthesis in the skeletal muscle.

Combined effect of branched-chain amino acids and taurine supplementation on delayed onset muscle soreness and muscle damage in high-intensity eccentric exercise.

BACKGROUND: Previous studies have evaluated the effectiveness of branched-chain amino acid (BCAA) supplementation for preventing delayed onset muscle soreness (DOMS) and muscle damage induced by eccentric exercise, their findings have been inconclusive. Since taurine has anti-inflammatory and anti-oxidative effects, the present study investigated the combined effect of BCAA and taurine on DOMS and muscle damage. METHODS: Thirty-six untrained male subjects (22.5 ± 3.8 years) were assigned to four groups (placebo + placebo [placebo], BCAA + placebo, placebo + taurine, and BCAA + taurine [combined]) and given a combination of 3.2 g BCAA (or placebo) and 2.0 g taurine (or placebo), three times a day, for two weeks prior to and three days after eccentric elbow flexor exercises. DOMS and muscle damage in the biceps brachii were subjectively and objectively evaluated using the visual analogue scale (VAS), upper arm circumference (CIR), and blood parameters (creatine kinase, lactate dehydrogenase [LDH], aldolase, and 8-hydroxydeoxyguanosine [8-OHdG]). RESULTS: In the combined group, VAS and 8-OHdG two days after exercise, CIR two and three days after exercise and LDH from one to three days after exercise were significantly lower than the placebo group. The area under the curve from before exercise to four days later for CIR, LDH, and aldolase was also significantly lower in the combined group than in the placebo group. CONCLUSION: A combination of 3.2 g BCAA and 2.0 g taurine, three times a day, for two weeks prior to and three days after exercise may be a useful nutritional strategy for attenuating exercise-induced DOMS and muscle damage.

Additional effects of taurine on the benefits of BCAA intake for the delayed-onset muscle soreness and muscle damage induced by high-intensity eccentric exercise.

Taurine (TAU) has a lot of the biological, physiological, and pharmocological functions including anti-inflammatory and anti-oxidative stress. Although previous studies have appreciated the effectiveness of branched-chain amino acids (BCAA) on the delayed-onset muscle soreness (DOMS), consistent finding has not still convinced. The aim of this study was to examine the additional effect of TAU with BCAA on the DOMS and muscle damages after eccentric exercise. Thirty-six untrained male volunteers were equally divided into four groups, and ingested a combination with 2.0 g TAU (or placebo) and 3.2 g BCAA (or placebo), thrice a day, 2 weeks prior to and 4 days after elbow flexion eccentric exercise. Following the period after eccentric exercise, the physiological and blood biochemical markers for DOMS and muscle damage showed improvement in the combination of TAU and BCAA supplementation rather than in the single or placebo supplementations. In conclusion, additional supplement of TAU with BCAA would be a useful way to attenuate DOMS and muscle damages induced by high-intensity exercise.

Effect of taurine supplementation on the alterations in amino Acid content in skeletal muscle with exercise in rat.

Taurine included abundantly in skeletal muscle, particularly in the slow-twitch fibers, enhances exercise performance. However, the exact mechanisms for this effect have been unclear. The present study investigated the influence of taurine supplementation on amino acids profile in skeletal muscles as one of mechanisms in the enhancement of exercise performance induced by taurine. In the rats that received taurine solution, amino acids concentrations were comprehensively quantified in two portions with different fiber compositions in the fast-twitch fiber dominant (FFD) gastrocnemius muscle after 2 weeks, and in the gastrocnemius and additional other FFD muscles, liver, and plasma with exhausted exercise after 3 weeks. In the FFD muscles after 2 weeks, a common phenomenon that decreased concentrations of threonine (-16%), serine (-15~-16%), and glycine (-6~-16%) were observed, and they are categorized in the pyruvate precursors for hepatic gluconeogenesis rather than biosynthesis, polar, and side-chain structures. The decreases in the three amino acids were significantly emphasized after an additional week of taurine supplementation in the FFD muscles (p values in three amino acids in these tissues were less than 0.001-0.05), but not in the liver and plasma, accompanied with significantly increase of running time to exhaustion (p <0.05). In contrast, the three amino acids (threonine and serine; p < 0.05, glycine; p < 0.01) and alanine (p < 0.01) in the liver were significantly decreased and increased, respectively, following the exhaustive exercise. In conclusion, the taurine-induced reductions of these amino acids in skeletal muscle might be one of the mechanisms which underpin the enhancement of exercise performance by taurine. Key pointsTaurine ingestion significantly decreased certain amino acids in skeletal muscles accompanied with enhanced exercise performance.The decreased amino acids in common were threonine, serine, and glycine, but not alanine; pyruvate precursor for gluconeogenesis.The alteration of three amino acids in muscles was maintained after exhausted exercise.The muscular alterations of them might be one of taurine-induced roles on exercise performance.