in skeletal muscle ( McKay et al., 2009 ). High-intensity exercise also increases blood myoglobin levels, indicating muscle damage, which can stimulate muscle growth in an untrained state, but muscle damage is likely not necessary in a trained state to induce muscle hypertrophy ( Damas et al., 2016
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Stephen M. Cornish, Jeremie E. Chase, Eric M. Bugera, and Gordon G. Giesbrecht
David C. Nieman, Courtney L. Capps, Christopher R. Capps, Zack L. Shue, and Jennifer E. McBride
Discovery, Gaithersburg, MD). All samples and provided standards were analyzed in duplicate, and the intraassay coefficient of variation (CV) ranged from 1.7% to 7.5% and the interassay CV ranged from 2.4% to 9.6% for all cytokines measured. C-Reactive Protein, CK, and Myoglobin C-reactive protein (CRP) and
John G. Seifert, Ronald W. Kipp, Markus Amann, and Oladele Gazal
This study examined energy and fluid supplementation on indices of muscle damage during alpine skiing. Skiers were assigned to a carbohydrate-protein (CP), placebo (PL), or no fluid (NF) group. CP and PL ingested 1.62 L during and after skiing. Myoglobin did not change from pre-skiing (PS) to 2 h post-skiing (2PS) for CP (24.8 ± 1.4 and 25.6 ± 1.6 ng/mL), but rose significantly from 26.4 ± 1.3 to 40.0 ± 2.8 ng/mL for PL and from 29.0 ± 1.3 to 82.9 ± 3.6 ng/mL for NF. Creatine kinase was maintained from PRE to 2 PS for CP, but increased significantly from 117 ± 7.2 to 174 ± 43.4 U/L for PL and from 126 ± 23.2 to 243 ± 34.3 U/L for NF. This study demonstrates that ingestion of a CP beverage minimized muscle damage indices during skiing compared to PL and NF and that ingesting fluids may also minimize muscle damage compared to a NF condition.
Yoshiharu Shimomura, Asami Inaguma, Satoko Watanabe, Yuko Yamamoto, Yuji Muramatsu, Gustavo Bajotto, Juichi Sato, Noriko Shimomura, Hisamine Kobayashi, and Kazunori Mawatari
The authors examined the effect of branched-chain amino acid (BCAA) supplementation on squat-exercise-induced delayed-onset muscle soreness (DOMS) using 12 young, healthy, untrained female participants. The experiment was conducted with a crossover double-blind design. In the morning on the exercise-session day, the participants ingested either BCAA (isoleucine:leucine:valine = 1:2.3:1.2) or dextrin at 100 mg/kg body weight before the squat exercise, which consisted of 7 sets of 20 squats/set with 3-min intervals between sets. DOMS showed a peak on Days 2 and 3 in both trials, but the level of soreness was significantly lower in the BCAA trial than in the placebo. Leg-muscle force during maximal voluntary isometric contractions was measured 2 d after exercise (Day 3), and the BCAA supplementation suppressed the muscle-force decrease (to ~80% of the value recorded under the control conditions) observed in the placebo trial. Plasma BCAA concentrations, which decreased after exercise in the placebo trial, were markedly elevated during the 2 hr postexercise in the BCAA trial. Serum myoglobin concentration was increased by exercise in the placebo but not in the BCAA trial. The concentration of plasma elastase as an index of neutrophil activation appeared to increase after the squat exercise in both trials, but the change in the elastase level was significant only in the placebo trial. These results suggest that muscle damage may be suppressed by BCAA supplementation.
Kazunori Nosaka, P.▀ Sacco, and K.▀ Mawatari
This study investigated the effect of a supplement containing 9 essential and 3 non-essential amino acids on muscle soreness and damage by comparing two endurance exercise bouts of the elbow fexors with amino acid or placebo supplementation in a double blind crossover design. The supplement was ingested 30 min before (10 h post-fasting) and immediately after exercise (Experiment 1), or 30 min before (2-3 h after breakfast), immediately post, and 8 more occasions over 4-day post-exercise (Experiment 2). Changes in muscle soreness and indicators of muscle damage for 4 days following exercise were compared between supplement conditions using two-way ANOVA. No significant differences between conditions were evident for Experiment 1; however, plasma creatine kinase, aldolase, myoglobin, and muscle soreness were significantly lower for the amino acid versus placebo condition in Experiment 2. These results suggest that amino acid supplementation attenuates DOMS and muscle damage when ingested in recovery days.
Zeynep Hazar Kanik, Seyit Citaker, Canan Yilmaz Demirtas, Neslihan Celik Bukan, Bulent Celik, and Gurkan Gunaydin
, maximal isometric quadriceps strength, vertical jump height, and blood analyses (creatine kinase [CK], lactate dehydrogenase [LDH], myoglobin, and C-reactive protein). Power analysis indicated that the required sample size to evaluate a time × group interaction (with 80% of statistical power and P < .05
Philippe Richard and François Billaut
used to calculate micromolar changes in tissue oxyhemoglobin–oxymyoglobin ([O 2 HbMb]), deoxyhemoglobin–deoxymyoglobin ([HHbMb]), and total hemoglobin–myoglobin ([THbMb] = [O 2 HbMb] + [HHbMb])—an index of change in regional blood volume. 23 The equilibrium between oxygen supply and consumption was
Jaehong Kim, Jeung Yeol Jeong, and Daeho Kim,
with ER on the third day (CPK = 3,060 IU/L, standard normal range in CPK = 32–294 IU/L; myoglobin > 900 ng/ml; standard normal range in myoglobin = 0–48.8 ng/ml; urine color = straw yellow). His kidney function was normal with no acute kidney injury or hyperkalemia. The player was hospitalized for
Cristiano D. da Silva and Ric Lovell
). Following the manufacturer’s instructions, 20 µL of plasma samples were mixed with 1.0 mL of working reagent. Absorbance readings were measured at 340 nm following a 2-minute incubation at 37°C, with readings repeated after 1, 2, and 3 minutes. Myoglobin (Mb) was determined (Dimension Vista ® Flex
Mads S. Larsen, Dagmar Clausen, Astrid Ank Jørgensen, Ulla R. Mikkelsen, and Mette Hansen
measurements, and questionnaires. The blood samples were analyzed for markers of muscle damage (creatine kinase [CK], lactate dehydrogenase [LDH], and myoglobin [Mb]) and cortisol. All meals during the study were provided by the research team and controlled for energy and macronutrient content. Prior to giving
