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Post Exercise (post + exercise)
Selected AbstractsEffect of conditioning horses with short intervals at high speed on biochemical variables in bloodEQUINE VETERINARY JOURNAL, Issue S36 2006A. LINDNER Summary Reasons for performing study: There is limited published work on the effect of training using intensive and short intervals of exercise to condition horses for racing. Objectives: To examine the effect of conditioning horses 1, 2 or 3 x a week using 2 short fast exercise intervals on blood lactate (LA), plasma ammonia (NH3) and urea (urea) as well as creatine kinase (CK) activity. Methods: Thoroughbreds (age 4,5 years) were conditioned at near maximal speed (12,14 m/sec) over 100 m, on 2 occasions separated by a 10 min period at walk, on dirt track (conditioning exercise; CE) during a 6 week conditioning period (CP). The CE was undertaken either once (5 horses), twice (5 horses) or 3 times a week (4 horses) during a CP. Before, every 2 weeks during and after the CP, blood was drawn during the CE at 0, 2 and 4 min after each run and additionally 6 min after the 2nd run to measure blood LA and determine the maximal LA post exercise (LAmax). Plasma NH3 was measured in the same samples and the maximal NH3 post exercise (NH3max) determined. Additional blood samples were taken from the horses when stabled before the CE, and 12 and 24 h after to measure urea and CK activity in plasma. Results: There was no differential effect of the number of weekly CE on LAmax, NH3max, LA and NH3 immediately after exercise (LAO and NH30). Conditioning did not have an effect on LAmax and LAO after the 1st interval (P>0.05), but LAO after the 2nd interval was lower after conditioning. NH3max after the 1st and 2nd exercise interval decreased in response to the conditioning, but not NH3 immediately after exercise (P>0.05). Median plasma CK activity 12 h after exercise was higher than before exercise and returned to pre-exercise levels 24 h post exercise when horses were exercised once and twice/week. In contrast, the median plasma CK activity of horses exercising 3 times/week remained at the pre-exercise level 12 and 24 h post exercise (P>0.05). Conclusion: Conditioning horses with 2 intervals of 100 m at near maximal speed had a positive effect on blood LA and plasma NH3. Potential relevance: With the type of exercise examined, the fitness of racing horses can be maintained and eventually improved. In further studies the effect of increasing the number of runs in one exercise session should be investigated. [source] Muscle, tendon, and somatotropin responses to the restriction of muscle blood flow induced by KAATSU-walk trainingEQUINE VETERINARY JOURNAL, Issue S36 2006T. ABE Summary Objective: The efficacy of KAATSU training has been demonstrated in human athletes, both as a therapeutic method as well as a training aid. The purpose of this study was to investigate the effects of slow walk training combined with restriction of muscle blood flow (KAATSU) on muscle and tendon size. Methods: Six healthy, unfit Standardbred mares performed walking (240 m/min for 10 min and then 5 min recovery) with KAATSU, and 6 mares performed walking without KAATSU. A specially designed elastic cuff1 was placed at the most proximal position of the forelegs and inflated to a pressure of 200,230 mmHg throughout the walking and recovery sessions. The training was conducted once a day, 6 days/week for 2 weeks. Skeletal muscle thickness and tendon thickness were measured using B-mode ultrasound at baseline and after 2 weeks of training. Venous blood samples were obtained before the first acute exercise and 5, 15 and 60 min afterwards. Serum somatotropin concentration was determined using a commercially available equine-specific ELISA kit. Results: The acute increase in plasma somatotropin was 40% greater (P<0.05) in the KAATSU-walk group than in the Control-walk group 5 min after exercise and remained elevated (P<0.05) at 15 and 60 min post exercise compared with the Control-walk group. After 2 weeks of training, muscle thickness increased (P<0.05) 3.5% in the KAATSU-walk group but did not change in the Control-walk group (0.7%). Tendon thickness did not change (P>0.05) in either group. Conclusions: These data demonstrate that KAATSU training can induce muscle hypertrophy in horses and suggest that KAATSU training may provide significant therapeutic/rehabilitative value in horses, as has been shown in man. [source] Haematological and respiratory gas changes in horses and mules exercised at altitude (3800 m)EQUINE VETERINARY JOURNAL, Issue S36 2006H. M. GREENE Summary Reason for performing study: Despite the common use of equids as visitors to high altitude mountainous environments, there are a paucity of carefully orchestrated scientific approaches. Further, again as a function of a common perceived advantage of mules over horses in these similar environments there are needs for controlled comparisons between these 2 equids. Objective: To measure haematological and respiratory function in horses and mules at low altitude (225 m), at rest and post exercise. In addition the rate and magnitude of these changes were followed over a 13 day period at high altitude (3800 m) to contrast acclimatisation. Methods: Resting and exercise venous blood samples (1 min post exercise) were obtained from 6 horses and 5 mules housed at 225 m (LA) and then transported to 3800 m (HA) for 13 days. The standardised exercise tests at both LA and HA consisted of trotting (3.0 m/sec) up an incline (6%) for 2 km. Data were analysed with repeated measures ANOVA (comparison of altitude acclimatisation and species) for changes in haematological and respiratory gases. Results: At low altitude, no group differences were found with both resting (P=0.69) and exercising (P=0.74) heart rates. Resting PCV was 8% lower in the mules (P=0.02) and 20% lower during exercise (P=0.02). Horses had significantly higher 2,3-diphosphoglycerate (2,3-DPG)/g Hb at both rest (P=0.003) and exercise (P=0.03). Exercise at HA increased PCV (P=0.03) in both groups, but the increase was attenuated in the mules compared to horses. The increase with 2,3-DPG/g Hb was expressed at HA in both groups (P=0.001) and was also attenuated in mules (P=0.03). Both groups were alkalotic compared to LA (P=0.001), and there were no group differences (P = 0.95). Conclusion: Of the variables measured, the most notable distinction between species was identified for only PCV and 2,3-DPG with both higher in horses, at both LA and HA. While the attenuated response of PCV in mules for the same exercise might argue for an improved adaptation to altitude, the lower 2,3-DPG might not. Other variables during the exercise bout were not different between species. [source] The efficacy of dantrolene sodium in controlling exertional rhabdomyolysis in the Thoroughbred racehorseEQUINE VETERINARY JOURNAL, Issue 7 2003J. G. T. Edwards Summary Reasons for performing study: Dantrolene sodium (Dantrium) has been used extensively for the treatment of myopathies in man and anecdotal evidence suggests it is of clinical benefit in the control of exercise-induced rhabdomyolysis (ER) in racehorses, although data to support this are currently lacking. Objectives: To investigate the efficacy of oral dantrolene sodium in controlling ER in a randomised, double-blind, placebo-controlled crossover trial involving 77 Thoroughbred racehorses in Newmarket, UK. Methods: Horses were treated on 2 occasions 1 week apart, with treatment days coinciding with a return to exercise following 2 days box rest on each occasion. For the first treatment, each horse was randomly selected to receive either 800 mg dantrolene sodium or a colour- matched placebo administered orally 1 h before exercise. This was followed by crossover to the other treatment on the second occasion, with each horse thereby acting as its own control. Degree of ER was assessed using rising serum creatine kinase (CK) levels, by subtracting pre-exercise blood CK levels from those measured in 6 h post exercise blood samples. For each horse, the difference in change between pre- and post exercise CK values between placebo and dantrolene treatments was calculated, with positive values indicating a greater rise with placebo than with dantrolene sodium treatment. Results: The overall mean difference for all horses was +104.8 iu/l and the null hypothesis, that there was no true difference in non-normally distributed post exercise rises in CK values between placebo and dantrolene treatments, was rejected (P = 0.0013) using the nonparametric Wilcoxon signed rank test. Additionally, no horses given dantrolene sodium showed clinical signs of ER, whereas 3 horses given the placebo developed ER following exercise. The incidence of ER in the study was 4% (3/77). Conclusions: The results confirmed that oral administration of dantrolene sodium, 1 h before exercise, had a statistically significant effect on reducing the difference between pre - and post exercise plasma CK levels compared with a placebo in the same animals, and preventing clinical ER in susceptible individuals. Potential relevance: This study suggested that dantrolene sodium is of use in controlling ER in the Thoroughbred racehorse. Further investigation into pre- and post exercise myoplasmic calcium levels and the repeat of the study late in the season when horses receive a much higher energy ration and more strenuous exercise would appear to be warranted. [source] Immediate blood pressure-lowering effects of aerobic exercise among patients with chronic kidney diseaseNEPHROLOGY, Issue 7 2008SAMUEL A HEADLEY SUMMARY: Aim: The current study was designed to determine the effect of moderate-intensity aerobic exercise on blood pressure responses within the laboratory for 60 min post exercise and in the subsequent 24 h period in patients with chronic kidney disease. Methods: Twenty-four subjects with stages 2,4 chronic kidney disease (age = 54.5 ± 15.2 years, body mass index = 32.0 ± 5.9 kg/m2) on antihypertensive medication completed this study. In random counterbalanced order, subjects were asked to either walk for 40 min at 50,60% VO2peak (oxygen consumption) or, on a separate day, to sit quietly in the laboratory for the same length of time. Following exercise or the non-exercise period, blood pressure was taken at 10 min intervals for 60 min. Subjects then wore an ambulatory blood pressure monitor for the next 24 h. Results: Systolic blood pressure (mmHg) was reduced by 6.5 ± 10.8 compared with the pre-exercise baseline value (130.3 ± 21.1) in the laboratory after exercise and this was greater than after the control period (0.73 ± 10.3, P < 0.05). Diastolic blood pressure (mmHg) was reduced following exercise (2.5 ± 6.4) compared with the control period (2.1 ± 4.9, P < 0.05). The mean 24 h readings did not differ between exercise or non-exercise days. Conclusion: Acute aerobic exercise leads to reduced blood pressure for at least 60 min within the laboratory in chronic kidney disease patients. [source] Exercise induces expression of leukaemia inhibitory factor in human skeletal muscleTHE JOURNAL OF PHYSIOLOGY, Issue 8 2008Christa Broholm The leukaemia inhibitory factor (LIF) belongs to the interleukin (IL)-6 cytokine superfamily and is constitutively expressed in skeletal muscle. We tested the hypothesis that LIF expression in human skeletal muscle is regulated by exercise. Fifteen healthy young male volunteers performed either 3 h of cycle ergometer exercise at ,60% of (n= 8) or rested (n= 7). Muscle biopsies were obtained from the vastus lateralis prior to exercise, immediately after exercise, and at 1.5, 3, 6 and 24 h post exercise. Control subjects had biopsy samples taken at the same time points as during the exercise trial. Skeletal muscle LIF mRNA increased immediately after the exercise and declined gradually during recovery. However, LIF protein was unchanged at the investigated time points. Moreover, we tested the hypothesis that LIF mRNA and protein expressions are modulated by calcium (Ca2+) in primary human skeletal myocytes. Treatment of myocytes with the Ca2+ ionophore, ionomycin, for 6 h resulted in an increase in both LIF mRNA and LIF protein levels. This finding suggests that Ca2+ may be involved in the regulation of LIF in endurance-exercised skeletal muscle. In conclusion, primary human skeletal myocytes have the capability to produce LIF in response to ionomycin stimulation and LIF mRNA levels increase in skeletal muscle following concentric exercise. The finding that the increase in LIF mRNA levels is not followed by a similar increase in skeletal muscle LIF protein suggests that other exercise stimuli or repetitive stimuli are necessary in order to induce a detectable accumulation of LIF protein. [source] | ||||||||||