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Biomedical subjects

V Vihko

Publications and source records attributed to V Vihko.

At least 19 recordsLinked to original sources
PubMed2005

Physiological and psychological responses to 100 km cross-country skiing during 2 days.

AIM: Physical exercise can have beneficial as well as detrimental effects on body tissues. The purpose of this study was to examine how the body responds to a 2-day 100 km ski event. METHODS: Two-day follow-up, field trial to measure changes in body mass, postural response of heart rate, pain perception, range of joint movement, muscle circumferences, vertical jump, creatine kinase (CK) and profile of mood state to repeated long distance cross-country skiing during 2 days. SUBJECTS: 10 physically active men (34.8+/-9.7 y, 1.82+/-0.05 m, 76.1+/-6.6 kg, BMI: 23.0+/-1.5. kgxm-2) participating in the Finlandia Ski Race, covering a total distance of 100 km during 2 days. RESULTS: Cardiorespiratory loading was high (over 85% of the maximal heart rate). However, leg measurements showed no signs of edema or a decline in flexibility or functional strength. CONCLUSION: SUBJECTS with excellent aerobic fitness are able to ski at high intensity a total of 100 km over 2 successive days without any major adverse effects on the musculoskeletal system or mood state.

Adult↗
PubMed2004

Hormonal responses to 100 km cross-country skiing during 2 days.

AIM: The purposes of this study were to investigate the resting levels and the acute hormonal responses of serum testosterone and cortisol, and with time-resolved immunofluorometric assay of luteinising hormone (LH) and follicle stimulating hormone (FSH), to daily repeated prolonged skiing. METHODS: Quasi-experimental design: short-term follow-up, (reversal) field trial to investigate the daily responses of blood hormones to repeated 50 km skiing during 2 days in men. PARTICIPANTS: 10 physically active men (34.8+/-9.7 y, 1.82+/-0.05 m, 76.1+/-6.6 kg, BMI: 23.0+/-1.5 kg.m(-2)) participating in the Finlandia Ski Race, covering a total distance of 100 km during 2 days. MEASURES: venous blood samples were obtained before and after skiing, and after 1 week's recovery, to determine the concentrations of testosterone, LH, FSH and cortisol in the blood. RESULTS: Testosterone was reduced by over 20% after both days (p=0.016 and 0.002, respectively). LH decreased after the 1( st) race by 37% and after the 2nd race by 44% (p=0.028, both). FSH secretion was stable and cortisol increased 2.2- and 2.6-fold after the races (p<0.001). CONCLUSIONS: The participants in the 2 days' prolonged skiing exercise went through a period of heavy physical stress. They showed changes in their serum testosterone, LH and cortisol concentrations, which, with the exception of the FSH secretion, alter the acute responses of both the adrenal cortex and the hypothalamus-pituitary-testicular axis. When training or competition programmes are planned it should taken into consideration that daily repeated high intensity prolonged skiing without a recovery day may cause hormonal overreaching.

Adult↗
PubMed2000

The effect of physical activity on breast cancer risk: a cohort study of 30,548 women.

BACKGROUND: In epidemiological studies abundant physical activity has been related to decreased breast cancer risk, though the results have been inconsistent. The purpose of this paper was to study the association of physical activity at leisure and commuting to work and incidence of breast cancer. METHODS: The study cohort consisted of 30,548 female participants of the Finnish adult health behaviour survey, based on annual random samples of Finns aged 15-64, collected in 1978-1993. By the end of 1995, 332 breast cancer cases had been diagnosed in the cohort. Relative risks of breast cancer were adjusted for age at survey, body mass index (BMI), education, length of follow-up, parity and age at first birth using Poisson regression models. RESULTS: Compared to women exercising less than once a week, the adjusted relative risk of breast cancer for women exercising once a week was 0.80 (95% confidence interval (CI): 0.58-1.10), for women exercising 2-3 times per week 0.92 (95% CI: 0.78-1.22) and for women exercising daily 1.01 (95% CI: 0.72-1.42). Women who reported commuting, walking or bicycling to work 30 min or more daily had slightly lower adjusted risk of breast cancer (RR: 0.87, 95% CI: 0.62-1.24) than women working at home, being unemployed or driving a car to working place. CONCLUSION: Although a small protective effect of regular physical activity for breast cancer incidence was found in physical activity when commuting to work, the role of the physical activity in breast cancer prevention is still an open question.

Adolescent↗
PubMed2000

Albumin clearance from human skeletal muscle during prolonged steady-state running.

This study was designed to find out if the lymph flow, indicated as albumin clearance, from active skeletal muscle is maintained constant during a prolonged steady-state exercise. 99mTc-labelled albumin was injected bilaterally into the vastus lateralis muscles of eight endurance-trained men. The radioactivity at the injection site was monitored by a gamma-camera before, frequently during, and after a 2 h run at a controlled steady intensity of 69 +/- 4% of the maximal heart rate. The fractional clearance rate of albumin was calculated for each monitoring interval, and was expressed as percentage clearance per minute (% min(-1)). During the first 15 min of exercise the clearance rate was five times higher than at rest before the exercise (0.29 +/- 0.12 vs. 0.06 +/- 0.05% min(-1), P = 0.001). During the next 25 min of running the clearance rate fell to 0.19 +/- 0.08% min(-1) (P = 0.02), from which level it was further attenuated, being 0.12 +/- 0.04% min(-1) at the end of the exercise. After the exercise the clearance rate fell rapidly to the level of 0.04 +/- 0.03% min(-1). The results showed that the albumin clearance from working muscles is not constant during steady-state exercise, suggesting that lymph flow from exercising skeletal muscle may not be constant despite lymphatic pumping being assumed to be unchanged during the course of exercise (i.e. constant exercise intensity and running speed).

Adult↗
PubMed1999

Increased mRNAs for procollagens and key regulating enzymes in rat skeletal muscle following downhill running.

The purpose of the study was to investigate pre-translational regulation of collagen expression after a single bout of exercise. We analysed steady-state messenger ribonucleic acid (mRNA) levels for collagen types I, III and IV, alpha- and beta-subunits of prolyl 4-hydroxylase and lysyl oxidase (enzymes modifying procollagen chains), and enzyme activity of prolyl 4-hydroxylase from rat soleus muscle (MS) and the red parts of quadriceps femoris muscle (MQF) after 12 h and after 1, 2, 4, 7 and 14 days of downhill (-13.5 degrees ) treadmill running at a speed of 17 m.min-1 for 130 min. Histological and biochemical assays revealed exercise-induced muscle damage in MQF but not MS. Steady-state mRNA levels for the alpha- and beta-subunits of prolyl 4-hydroxylase in MQF, lysyl oxidase in MS and MQF were increased 12 h after running, whereas prolyl 4-hydroxylase activity did not increase until 2 days after exercise. The mRNA levels for the fibrillar collagens (I and III) and basement membrane type IV collagen significantly increased 1 day and 12 h after exertion, respectively. Peak mRNA levels were observed 2-4 days after running, the increases being more pronounced in MQF than in MS. No significant changes were observed in types I or III collagen at the protein level. Strenuous downhill running thus causes an increase in gene expression for collagen types I and III and their post-translational modifying enzymes in skeletal muscle in a co-ordinated manner. These changes, together with the increased gene expression of type IV collagen, may represent the regenerative response of muscle extracellular matrix to exercise-induced injury and an adaptive response to running exertion.

Animals↗
PubMed1999

Gender differences in skeletal muscle fibre damage after eccentrically biased downhill running in rats.

Specific antibodies against structural proteins of muscle fibres (actin, desmin, dystrophin) and extracellular matrix (fibronectin) were used to study the effect of eccentrically biased downhill running exercise (13,5 degrees, 17 m min(-1), 130 min) on the magnitude and properties of myofibre injury in the quadriceps femoris muscle of male and female rats. Muscle beta-glucuronidase activity, a quantitative indicator of muscle damage, showed clearly smaller increase in female than in male rats during the 4-day period following exercise. A similar course of histopathological changes was observed in both sexes, although females showed slower and less marked changes than males. In males, discontinuous or even lost submembrane protein dystrophin staining was observed in some swollen fibres immediately after exercise, before the loss of desmin and staining of disorganized actin, i.e. before the disruption of the cytoskeletal system and the contractile apparatus. The observation that no dramatic changes in the microarchitecture of the muscle fibres were detected immediately or even 6 h after the exercise in females compared with males may indicate that the sarcolemma of the females might be strengthened against membrane damage by a still unknown stabilizing compound.

Actins↗
PubMed1999

Neck muscle ultrasonography of male weight-lifters, wrestlers and controls.

The purpose of this cross-sectional study was to evaluate the effect of different sport training regimens on the size of the neck semispinalis capitis muscle (SECM). The cross-sectional area (CSA) and the linear dimensions of the SECM were measured bilaterally by real-time ultrasonography. Ten young Finnish elite level weight-lifters, 8 freestyle wrestlers and 10 controls (all male) participated in the study. Muscle CSA was significantly larger in wrestlers than in weight-lifters or controls (P < 0.001). There was no significant difference in size between the right and left SECM in any of the subject groups, but the variation between sides (smaller vs. larger) was significantly higher in wrestlers than weight-lifters (P < 0.05). CSA correlated with the multiplied linear dimensions (r = 0.80, P < 0.000). Neck muscle: ultrasonography appeared to be a useful method in evaluating the differences between two groups of athletes.

Adult↗
PubMed1998

Neck semispinalis capitis muscle size in sitting and prone positions measured by real-time ultrasonography.

OBJECTIVE: To examine the reliability of measurements of semispinalis capitis muscle (SECM) cross-sectional area (CSA) in prone and sitting positions, and to compare the muscle size in these two positions. DESIGN: Semispinalis capitis CSA was measured twice a day on two successive days with a real-time ultrasound apparatus. SUBJECTS: Eighteen males (aged 19-34 years) and 28 females (aged 19-34 years) were studied for the reliability test. Seven males and 12 females were randomly selected to compare SECM size in sitting and prone positions. RESULTS: The intraclass correlation coefficient (ICC) for repeatability measurements was r = 0.98 for the two positions. The correlation of the CSA in sitting and in prone positions was r = 0.93 (p < 0.01). There were no significant differences between CSA, linear dimensions and shape ratio of SECM in the two positions. CONCLUSIONS: In this study SECM ultrasonography appeared to be an accurate method in both positions, and position as such had no significant effects on the SECM cross-sectional size. Such accuracy allows neck muscle evaluation in clinical diagnosis and in follow-up studies during neck rehabilitation programmes.

Adult↗
PubMed1998

Relationship between the risk of breast cancer and physical activity. An epidemiological perspective.

The possible protective effect of physical exercise on the risk of breast cancer has gained attention during the last few years. According to the current concepts of biological mechanisms underlying the possible protection, physical activity may alter menstrual function by reducing the number of ovulatory menstrual cycles via a hormone-related pathway and, thus, reducing the cumulative exposure to progesterone and estrogen. Experimental studies on the effects of exercise suggest changes in menstrual characteristics and in ovarian hormone serum levels. The majority of epidemiological studies, in spite of limitations in estimating physical activity and partly incomplete control of confounding factors, suggest a protective effect of physical activity. Whether physical activity offers a means of primary prevention of breast cancer is still an open issue.

Breast Neoplasms↗
PubMed1997

Lymph flow dynamics in exercising human skeletal muscle as detected by scintography.

1. The effects of dynamic and isometric muscle contractions on the lymph flow dynamics in human skeletal muscle were studied with a scintographic method. 2. Radioactively labelled human serum albumin (99mTc-HSA) was injected bilaterally into the vastus lateralis muscles of eight men (n = 16), four of whom had had an endurance training background. The subjects performed 100 submaximal contractions in 10 min as (i) dynamic knee extensions (CONS), (ii) isometric contractions with the knees at full extension (IMExt), or (iii) isometric contractions with knees fixed at 90 deg angle flexion (IMFlex). The exercises were separated by 65 min periods in supine rest. The level of radioactivity at the injection site was monitored by a gamma-camera, and the clearance rate of radioactivity (CR) was calculated as the fractional decrease during the periods of interest (CR unit = % min-1). 3. The clearance rate was low during the rest periods (0.04 +/- 0.05% min-1), though higher in the trained than in the sedentary subjects (0.06 +/- 0.05 vs. 0.03 +/- 0.03% min-1; P = 0.008). Exercise increased the clearance rate three- to sixfold, to 0.16 +/- 0.16% min-1 during CONS, 0.20 +/- 0.15% min-1 during IMExt and 0.09 +/- 0.11% min-1 during IMFlex. There were no differences between the subject subgroups. 4. The higher clearance rate during IMExt than during IMFlex (P = 0.02) demonstrates the importance of muscle deformations on lymph propulsion and experimentally confirms the current concepts of lymph formation and propulsion in voluntarily active skeletal muscle. It is suggested that lymph propulsion by working muscle is most efficient when the muscle is able to shorten close to its minimum length.

Adult↗
PubMed1997

Exercise-induced increase in serum creatine kinase is modified by subsequent bed rest.

This study was designed to find out if bed rest, which is known to markedly reduce peripheral lymph flow, immediately after strenuous exercise could affect the behaviour of creatine kinase activity (CK) in serum. Eleven endurance athletes performed an 18 km cross-country run, after which six of the subjects were placed in bed rest group (BR) for 23 hours, while a group of five control subjects maintained their normal habitual activity (C). After the bed rest all subjects performed a light jogging bout for 45 min. Seven hours after the exercise serum CK was increased threefold (p < 0.05) in both groups. During the next 16 hours serum CK increased further 30% in C (p < 0.05) but decreased (p < 0.05) in a similar magnitude in BR. Light jogging elicited a transient CK increase of 16% (p < 0.05) in C, but there was no change in BR. The fact that serum CK increased similarly in both groups during the first hours after the exercise shows that the transport of CK from muscles into circulation can be maintained for some hours despite absence of muscular activity. However, the later post-exercise serum CK response may be diminished by bed rest (effect of posture and/or lack of muscle function). The reduced response is also seen in the CK response to a repeated exercise. These observations suggest that a short-term physical inactivity (bed rest) may reduce both the lymphatic transport of CK and the release of enzyme from muscle fibres.

Adult↗
PubMed1997

The effects of a 4-day march on the lower extremities and hormonal balance.

The functional strength, flexibility, and ranges of motion of the lower extremities, as well as hormonal balance, estimated by urinary excretion of adrenaline and noradrenaline and serum determinations of testosterone and cortisol, were studied with six physically active army officers participating in a 4-day march totaling 185 km. Catecholamine excretion rates showed cumulatively increased sympathoadrenal stress, and the effects on serum testosterone and cortisol concentrations were minor. Also, leg measurements showed no signs of edema, decreases in flexibility, or decreases in functional strength. Most pain (75%) experienced by the subjects was located in the feet and caused by abrasions and blisters. Only a small portion of perceived pains (25%) was associated with muscle soreness. Serum creatine kinase activity was slightly (ca. 400-650%) increased during the marching days. Thus, soldiers who are in good physical condition and are accustomed to marching are able to walk four marathons on successive days, while carrying 10-kg backpacks, without any major adverse effects on the musculature of their lower extremities.

Adult↗
PubMed1996

Ultrasonography of the neck splenius capitis muscle. Investigation in a group of young healthy women.

PURPOSE: To evaluate the reproducibility of real-time ultrasonography as a method for measuring the size of the splenius capitis muscle (SPCM). MATERIAL AND METHODS: Ten right-handed women (non-athletes) aged 19-29 years were studied. Muscle cross-sectional area (CSA), anterior-posterior dimension (APD), and lateral dimension (LD) were measured bilaterally on 2 successive days, twice each day. RESULTS: The coefficient of variation (CV) of CSA was 2.7% between times, and 3.0% between days. No significant correlations were found between muscle CSA and the anthropometric variables (neck girth, height, weight, fat percentage and body mass index). A significant correlation between CSA and the multiple of the 2 linear dimensions (MLD = LD x APD) was found (r = 0.76, p = < 0.01). CSA of SPCM was larger on the dominant side (p < 0.05). CONCLUSION: The results suggest that real-time ultrasonography is a useful method for evaluating the size of the SPCM.

Adult↗
PubMed1995

Does increased serum creatine kinase activity reflect exercise-induced muscle damage in rats?

To test a hypothesis that exercise-induced increase in serum creatine kinase activity and the concomitant necrotic muscle damage in unaccustomed rats may be interrelated phenomena, and that the first might largely be caused by changes in lymph flow, groups of rats were separately exposed to a swimming, combination of swimming and running, and running protocol. Their serum was then repeatedly analysed over a period of 72 h for creatine kinase activity, and their soleus and the red parts of quadriceps femoris muscles for beta-glucuronidase activity (damage marker) 72 h after the commencement of the experiment, i.e. at a moment when muscle damage is in the necrotic phase. The results clearly showed that serum creatine kinase activity may increase without concomitant muscle damage (swimming protocol) and that muscle damage may occur without a statistically significant increase in serum creatine kinase activity (running protocol). Swimming followed by running increased creatine kinase activity more strongly than the separate protocols. Muscle damage was of a similar magnitude after running and after the combined exercise. The present results indicate that serum creatine kinase activity in rodent exercise myopathy is an inadequate indicator of injury both quantitatively and qualitatively.

Animals↗
PubMed1995

Training-induced protection and effect of terminated training on exercise-induced damage and water content in mouse skeletal muscles.

Muscle swelling in connection with training-induced protection against exercise-induced damage and the disappearance of the protective adaptation after termination of training was studied in male NMRI-mice, aged 8 weeks at the beginning of the experiment. Mice were randomly assigned to several different treatment groups (training, training-exercise, exercise, detraining, detraining-exercise, together with their respective controls). Training and prolonged exercise sessions were performed by running uphill (6 degrees) on a motor-driven treadmill. Muscle damage was estimated by the total activity of beta-glucuronidase and water content from the red parts of m. quadriceps femoris (MQF), m. soleus (MS), m. rectus femoris (MRF), and from m. triceps brachii (MTB). Training-induced protection was observed in MS after only one week of training. In MQF the protection was incomplete after 1 and 4 weeks' training. In MS the protection disappeared already one week after the cessation of training. In MQF the training-induced protection persisted in part for one week but after four-week's detraining no protection was observed. The present results suggest that diminution of muscle swelling forms part of the adaptation of skeletal muscle in resisting exercise damage, and, vice versa, increased susceptibility to exercise damage, which follows the termination of training, is linked to muscle reswelling.

Animals↗
PubMed1994

Dissociation of the effects of training on oxidative metabolism, glucose utilisation and GLUT4 levels in skeletal muscle of streptozotocin-diabetic rats.

The effects of long-term, moderate physical exercise on in vivo glucose uptake, levels of two glucose transporter proteins (GLUT1 and GLUT4) and activities of various key enzymes of energy metabolism were measured in skeletal muscle from streptozotocin-diabetic rats. Diabetes (12-16 weeks) reduced the in vivo glucose uptake (glucose metabolic index, GMI) in muscle containing mainly type I fibres by 55% but had no effect in muscles containing mainly type IIa and IIb fibres. GMI was increased in the diabetic white skeletal muscle (mainly type IIb fibres) by more than 120%. In contrast to the complex changes in GMI, GLUT4 levels were reduced in all types of skeletal muscle from diabetic rats with no change in GLUT1 levels. Exercise training had no effects on GMI or the glucose transporter levels. Streptozotocin induced diabetes significantly reduced the oxidative capacity of skeletal muscle assayed as the activities of citrate synthase, succinate dehydrogenase and cytochrome c oxidase. Training increased the activities of oxidative enzymes, with this increase being more prominent in the diabetic animals. The present data indicate that long-term streptozotocin-induced diabetes decreases oxidative metabolic capacity and GLUT4 protein levels in skeletal muscle, but that the changes of glucose transport largely depend on the fibre type composition. Moderate training fully reverses the effect of insulinopenia and hyperglycaemia on muscle oxidative metabolism. In contrast to the previous suggestions, the expression of GLUT4 is not correlated with the capacity of oxidative metabolism in skeletal muscle of streptozotocin-diabetic rats.

Animals↗
PubMed1994

Exercise-induced necrotic muscle damage and enzyme release in the four days following prolonged submaximal running in rats.

Male Wistar rats were made to run uphill on a treadmill 5.5 degrees incline at 17 m min-1 for 4 h, and killed for muscle and serum sampling 2, 4, 12, 24, 48 or 96 h after the exertion. To estimate the degree of muscle damage, beta-glucuronidase activity, total protein concentration, water content and morphology were examined in the red parts of quadriceps femoris (MQF) and soleus (MS) muscles, the distal white part of the rectus femoris muscle (MRF) and the superficial part of triceps brachii muscle (MTB). Simultaneous serum samples were assayed for creatine kinase (CK) activity and carbonic anhydrase III (CA III) concentration. Fibre swelling and interstitial oedema were detected in MS at 4 h and in MQF at 12 h and typical histopathological changes, including inflammation and fibre necrosis, in both muscles 12-96 h post-exertion. beta-Glucuronidase activity, a quantitative marker of muscle damage, was increased in MS at 4 h, in MQF at 24 h and in MRF 48 h after the running. No increase occurred in MTB. Water and protein content increased or decreased respectively, faster in MS (2 h post-exercise) than in MQF (12 h) or MRF (12 h). Water content thus contributed to muscle damage by preceding the increase in beta-glucuronidase activity. Serum CK activity was increased 2, 4, and 48 h after the running. Changes in serum CA III concentration were rather similar to those in CK but were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗