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Matthew R. Nelson, Robert K. Conlee and Allen C. Parcell

In Delayed Onset Muscle Soreness (DOMS), muscles become sore 24 to 48 hours after eccentric and unaccustomed activity. Fiber stiffness, due to decreased muscle glycogen, may predispose muscle to greater damage during eccentric exercise. This study sought to determine if inadequate carbohydrate intake following a protocol to decrease muscle glycogen would increase DOMS after 15 min of downhill running. Thirty-three male subjects (age, 18–35 years) were randomized into 3 groups for testing over a 7-day period. The depletion (DEP) group (n = 12) underwent a glycogen depletion protocol prior to a 15-min downhill run designed to induce DOMS. The repletion (FED) group (n = 10) underwent a glycogen depletion protocol followed by a carbohydrate repletion protocol (>80% CHO) prior to downhill running. The third (ECC) group (n = 11) performed only the downhill running protocol. Subjective muscle soreness, isometric force production, relaxed knee angle, and thigh circumference were measured pretreatment and on days 1, 2, 3, 4, and 6 post treatment. Subjective muscle soreness for all groups increased from 0 cm pretreatment to 3.05 ± 0.72 cm (on a 10-cm scale) on day 1 post treatment (p < .05). All groups were significantly different from baseline measurements until day 4 post treatment. Each group experienced a decline in isometric force from 281 ± 45 N pre-to 253 ± 13 N on day 1 post treatment (p < .05). The decrease in isometric force persisted in all groups for 4 days post treatment. Increases in thigh circumference and relaxed knee angle elevations in all 3 groups were statistically different (p < .05) from pretreatment until day 4. No differences were noted between groups for any of the parameters examined. In the current study, 15 min of downhill running is sufficient to cause DOMS with the associated functional and morphological changes; however, inadequate carbohydrate intake after a glycogen depleting exercise does not appear to exacerbate DOMS and the associated symptoms.

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Melissa Skein, Rob Duffield, Geoffrey M. Minett, Alanna Snape and Alistair Murphy

Purpose:

This study examined the effects of overnight sleep deprivation on recovery after competitive rugby league matches.

Methods:

Eleven male amateur rugby league players played 2 competitive matches, followed by either a normal night’s sleep (~8 h; CONT) or a sleep-deprived night (~0 h; SDEP) in a randomized fashion. Testing was conducted the morning of the match, immediately postmatch, 2 h postmatch, and the next morning (16 h postmatch). Measures included countermovement-jump (CMJ) distance, knee-extensor maximal voluntary contraction (MVC) and voluntary activation (VA), venous-blood creatine kinase (CK) and C-reactive protein (CRP), perceived muscle soreness, and a word–color recognition cognitive-function test. Percent change between postmatch and 16-h postmatch was reported to determine the effect of the intervention the next morning.

Results:

Large effects indicated a greater postmatch to 16-h-postmatch percentage decline in CMJ distance after SDEP than in CONT (P = .10–.16, d = 0.95–1.05). Similarly, the percentage decline in incongruent word–color reaction times was increased in SDEP trials (P = .007, d = 1.75). Measures of MVC did not differ between conditions (P = .40–.75, d = 0.13–0.33), although trends for larger percentage decline in VA were detected in SDEP (P = .19, d = 0.84). Furthermore, large effects indicated higher CK and CRP responses 16 h postmatch in SDEP than in CONT (P = .11–.87, d = 0.80–0.88).

Conclusions:

Sleep deprivation negatively affected recovery after a rugby league match, specifically impairing CMJ distance and cognitive function. Practitioners should promote adequate postmatch sleep patterns or adjust training demands the next day to accommodate the altered physical and cognitive state after sleep deprivation.

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Mindy Millard-Stafford, Gordon L. Warren, Leah Moore Thomas, J. Andrew Doyle, Teresa Snow and Kristen Hitchcock

Post-exercise nutrition is critical to facilitate recovery from training. To determine if added protein (P) or increased carbohydrate (CHO) differentially improves recovery, eight runners ingested: 6% CHO (CHO6), 8% CHO + 2% protein (CHOP), and isocaloric 10% CHO (CHO10) following a 21-km run plus treadmill run to fatigue (RTF) at 90% VO2max. RTF was repeated after 2 h recovery. After 24 h, a 5 km time trial was performed. Insulin and blood glucose were higher (P < 0.05) following CHO10 compared to CHO-P and CHO6, but did not affect improvement from the first to second RTF (29.6% ± 6, 40.5% ± 8.8, 40.5% ± 14.5) or 5 km time (1100 ± 36.3, 1110 ± 37.3, 1118 ± 36.5 s). CK was not different, but perceived soreness with CHO-P (2.1 ± 0.5) was lower than CHO10 (5.2 ± 0.7). Additional calories from CHO or P above that provided in sports drinks does not improve subsequent performance after recovery; but less soreness suggests benefits with CHO-P.

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Mary P. Miles, Erin E. Walker, Stephen B. Conant, Shelly P. Hogan and Jessy R. Kidd

Attenuation of exercise-induced interleukin-6 (IL-6) responses by carbohydrate (CHO) has been demonstrated in studies comparing controlled doses (≥ 0.9 g · kg−1 · h−1) to placebo, but not in studies of voluntary intake. This study sought to determine if attenuation of the IL-6 response during a 32.2-km mountain trail race occurs for high compared to low ad libitum CHO intakes. IL-6, C-reactive protein (CRP), and creatine kinase activity (CK) were analyzed from blood samples collected 12 h pre-, 0, 4, and 24 h post-race. Subjects were grouped into low (n = 14, 0.4 ± 0.1 g · kg−1· h−1) and high (n = 18, 0.8 ± 0.2 g · kg−1 · h−1) CHO intake groups. IL-6 0 h post-race (P < 0.05) was higher in the low (40.2 ± 22.7 pg · mL−1) compared to the high CHO group (32.7 ± 22.1 pg · mL−1). CRP and CK both increased post-race, but no differences were observed between groups. Attenuation of exercise-induced IL-6 is apparent across a range of CHO intakes.

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Michael S. Green, J. Andrew Doyle, Christopher P. Ingalls, Dan Benardot, Jeffrey C. Rupp and Benjamin T. Corona

This study determined whether disrupted glucose and insulin responses to an oral glucose-tolerance test (OGTT) induced by eccentric exercise were attenuated after a repeated bout. Female participants (n = 10, age 24.7 ± 3.0 yr, body mass 64.9 ± 7.4 kg, height 1.67 ± 0.02 m, body fat 29% ± 2%) performed 2 bouts of downhill running (DTR 1 and DTR 2) separated by 14 d. OGTTs were administered at baseline and 48 hr after DTR 1 and DTR 2. Maximum voluntary isometric quadriceps torque (MVC), subjective soreness (100-mm visual analog scale), and serum creatine kinase (CK) were assessed pre-, post-, and 48 hr post-DTR 1 and DTR 2. Insulin and glucose area under the curve (38% ± 8% and 21% ± 5% increase, respectively) and peak insulin (44.1 ± 5.1 vs. 31.6 ± 4.0 μU/ml) and glucose (6.5 ± 0.4 vs. 5.5 ± 0.4 mmol/L) were elevated after DTR 1, with no increase above baseline 48 hr after DTR 2. MVC remained reduced by 9% ± 3% 48 hr after DTR 1, recovering back to baseline 48 hr after DTR 2. Soreness was elevated to a greater degree 48 hr after DTR 1 (48 ± 6 vs. 13 ± 3 mm), with a tendency for greater CK responses 48 hr after DTR 1 (813 ± 365 vs. 163 ± 43 U/L, p = .08). A novel bout of eccentric exercise confers protective effects, with subsequent bouts failing to elicit disruptions in glucose and insulin homeostasis.

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Dylan Thompson, Clyde Williams, Stephen J. McGregor, Ceri W. Nicholas, Frank McArdle, Malcolm J. Jackson and Jonathan R. Powell

The aim of the present study was to investigate whether 2 weeks of vitamin C supplementation affects recovery from an unaccustomed bout of exercise. Sixteen male subjects were allocated to either a placebo (P; n = 8) or vitamin C group (VC; n = 8). The VC group consumed 200 mg of ascorbic acid twice a day, whereas the P group consumed identical capsules containing 200 mg of lactose. Subjects performed a prolonged (90-min) intermittent shuttle-running test 14 days after supplementation began. Post-exercise serum creatine kinase activities and myoglobin concentrations were unaffected by supplementation. However, vitamin C supplementation had modest beneficial effects on muscle soreness, muscle function, and plasma concentrations of malondialdehyde. Furthermore, although plasma interleukin-6 increased immediately after exercise in both groups, values in the VC group were lower than in the P group 2 hours after exercise (p < .05). These results suggest that prolonged vitamin C supplementation has some modest beneficial effects on recovery from unaccustomed exercise.

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Eduardo Lusa Cadore, Miriam González-Izal, Rafael Grazioli, Igor Setuain, Ronei Silveira Pinto and Mikel Izquierdo

adaptations, and eccentric contractions are characterized by greater muscle force output, high rehabilitation capacity, and greater muscle damage (ie, providing a protective effect). This greater muscle damage causes muscle stiffness and soreness in untrained subjects in the days following the exercise, 4 – 6

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Eric S. Rawson, Mary P. Miles and D. Enette Larson-Meyer

response to exercise via increased growth factor/gene expression, increased intracellular water; reduced symptoms of or enhanced recovery from muscle damaging exercise (e.g., DOMS); enhanced recovery from disuse, immobilization, or extreme inactivity such as after injury; improved cognitive processing

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Matthew David Cook and Mark Elisabeth Theodorus Willems

.g., thiobarbituric acid reactive substances, total antioxidant status, lipid hydroperoxides, and protein carbonyls) and inflammation (e.g., interleukin 6, tumor necrosis factor α, C-reactive protein) following muscle-damaging and metabolically demanding exercise ( Bell et al., 2014 , 2015 , 2016 ; Howatson et

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Adam R. Jajtner, Jay R. Hoffman, Adam M. Gonzalez, Phillip R. Worts, Maren S. Fragala and Jeffrey R. Stout

Context:

Resistance training is a common form of exercise for competitive and recreational athletes. Enhancing recovery from resistance training may improve the muscle-remodeling processes, stimulating a faster return to peak performance.

Objective:

To examine the effects of 2 different recovery modalities, neuromuscular electrical stimulation (NMES) and cold-water immersion (CWI), on performance and biochemical and ultrasonographic measures.

Participants:

Thirty resistance-trained men (23.1 ± 2.9 y, 175.2 ± 7.1 cm, 82.1 ± 8.4 kg) were randomly assigned to NMES, CWI, or control (CON).

Design and Setting:

All participants completed a high-volume lower-body resistance-training workout on d 1 and returned to the human performance laboratory 24 (24H) and 48 h (48H) postexercise for follow-up testing.

Measures:

Blood samples were obtained preexercise (PRE) and immediately (IP), 30 min (30P), 24 h (24H), and 48 h (48H) post. Subjects were examined for performance changes in the squat exercise (total repetitions and average power per repetition), biomarkers of inflammation, and changes in cross-sectional area and echo intensity (EI) of the rectus femoris (RF) and vastus lateralis muscles.

Results:

No differences between groups were observed in the number of repetitions (P = .250; power: P = .663). Inferential-based analysis indicated that increases in C-reactive protein concentrations were likely increased by a greater magnitude after CWI compared with CON, while NMES possibly decreased more than CON from IP to 24H. Increases in interleukin-10 concentrations between IP and 30P were likely greater in CWI than NMES but not different from CON. Inferential-based analysis of RF EI indicated a likely decrease for CWI between IP and 48H. No other differences between groups were noted in any other muscle-architecture measures.

Conclusions:

Results indicated that CWI induced greater increases in pro- and anti-inflammatory markers, while decreasing RF EI, suggesting that CWI may be effective in enhancing short-term muscle recovery after high-volume bouts of resistance exercise.