bluuebunny/crossref_metadata_2025 huggingface dataset:
Lactate/H+ transport in skeletal muscle from spinal‐cord‐injured patients
Authors: Pilegaard H. , Mohr T. , Kjaer M. , Juel C.
Published: July 2010

In order to evaluate the effect of prolonged muscle inactivity on sarcolemmal lactate/H+ transport in humans, the lactate/H+ transport capacity was determined in the thigh muscle of spinal‐cord‐injured (SCI) individuals. The lactate transport rate was measured in sarcolemmal giant vesicles produced by collagenase treatment of muscle biopsies obtained from the vastus lateralis muscle. Six SCI subjects with total loss of motor and sensory functions of their lower limbs participated in the study. The duration of the injury ranged from 2 to 15 years. The total lactate transport rate in the muscle of SCI patients was 46.5±2.6 pmol · cm−2· s−1 (mean±SEM), which corresponds to a 17% lower (P<0.05) transport rate than that found in healthy, untrained subjects. The estimated carriermediated lactate/H+ transport capacity was approximately 26% lower in the SCI patients than in healthy, untrained subjects. The observed muscle lactate/H+ transport capacity of SCI individuals is in accordance with a positive correlation between the capacity of the lactate/H+ transporters and the percentage occurrence of slow‐twitch fibres in a muscle, although there seems to be a wide range of transport capacities within each fibre type. The present results show that the sarcolemmal lactate/H+ transport capacity is lower in SCI individuals than in normally physically active subjects, which indicates that prolonged muscle inactivity reduces the lactate/H+ transport capacity of human muscle.
The relationship between achievement goal profile groups and perceptions of motivational climates in sport
Authors: Ntoumanis N. , Biddle S.
Published: July 2010

The purpose of the present study was to expand on previous research that has found compatibility between individuals’views on achievement and the type of achievement that was promoted in the sport environment they belonged to. However, this line of research has ignored the fact that the two main goal orientations are largely independent and that their impact in combination is often different from their effects examined separately. The present study, therefore, examined which combinations of goal orientations are compatible with perceptions of mastery and performance climates in a sample of 146 British university students. With regard to mastery climate, the analysis showed that the critical factor was the degree of task orientation since those with high scores in this factor (irrespective of the degree of their ego orientation) perceived the climate as more mastery‐oriented than those with low scores in task orientation. This was substantiated by the large differences in effect sizes between the high‐ and low‐task groups. As far as performance climate was concerned, the most negative perceptions of climate were held by those who were rated both low in task orientation and high in ego orientation. A general inference from these results is that high task orientation is motivationally adaptive, whereas high ego orientation is not motivationally detrimental as long as it is accompanied by a high task orientation. These findings are in contrast with previous suggestions that have called for the enhancement of task orientation with the concurrent suppression of ego orientation. Our results are, however, consonant with studies which have employed a goal profiles analysis in sport and in physical education, and with empirical evidence from real sport settings.
Acut badminton injuries
Authors: Fahlström M. , Björnstig U. , Lorentzon R.
Published: July 2010

During 1990‐1994, 1.2% of all sports injuries that required emergency care at the Universytiy Hospital of Umeå were caused by badminton. In 90.7% of the cases the patients described themselves as recreational players of beginners. There were 51.3% minor injuries (AIS 1) and 48.7% moderate injureis (AIS 2). The lower extremities were affected in 92.3% of the cases. Achilles tendon ruptures (34.6%) and ankle sprains and fractures (29.5%) were the most frequent. By the time of the follow‐up (10‐69 months), 52.6% of the players still had symptoms from the injuries and 39.5% had not been able to return to playing badminton. Our data indicate the importance of adequate treatment and rehabilitation after actue badminton injuries.
Aerobic endurance testing of children and adolescents—a comparison of two treadmill‐protocols
Authors: Fredriksen P. M. , Ingjer F. , Nystad W. , Thaulow E.
Published: July 2010

Fifty‐eight children and adolescents of both sexes, aged 8–16, were tested on a treadmill using two different protocols. The well‐known Bruce‐protocol has the disadvantages of steep incline and large increments at each step. A new protocol (Oslo‐protocol) with less incline and smaller increments was compared to the Bruce‐protocol. The results from the two protocols showed no differences with regard to peak oxygen uptake (VO2peak) or peak heart rate (HRpeak). However, the respiratory exchange ratio (R) and blood lactate concentration [La−] showed higher values when the Bruce‐protocol was used. The study also indicated that the often used criteria of HRpeak, R and achievement of a plateau in VO2 to estimate VO2peak, were not reliable indicators in either protocol. When time to exhaustion was used as an estimation of aerobic endurance level, the Oslo‐protocol discriminated better than the Bruce‐protocol. As a conclusion, the results indicate that none of the criteria may be used as a reliable indicator of having achieved VO2peak. An experienced testleader may be essential to define when VO2peak has been reached in children. On the basis of the results from the current study, the Oslo‐protocol seems suitable as a test‐protocol when testing children and adolescents for VO2peak.
Isokinetic eccentric exercise as a model to induce and reproduce pathophysiological alterations related to delayed onset muscle soreness
Authors: Lund H. , Vestergaard‐Poulsen P. , Kanstrup I.‐L. , Sejrsen P.
Published: July 2010

Physiological alterations following unaccustomed eccentric exercise in an isokinetic dynamometer of the right m. quadriceps until exhaustion were studied, in order to create a model in which the physiological responses to physiotherapy could be measured. In experiment I (exp. I), seven selected parameters were measured bilaterally in 7 healthy subjects at day 0 as a control value. Then after a standardized bout of eccentric exercise the same parameters were measured daily for the following 7 d (test values). The measured parameters were: the ratio of phosphocreatine to inorganic phosphate (PCr/Pi), the ratio of inorganic phosphate to adenosintriphosphate (Pi/ATP), the ratio of phosphocreatine to adenosintriphosphate (PCr/ATP) (all three ratios measured with 31P‐nuclear magnetic resonance spectroscopy), dynamic muscle strength, plasma creatine kinase (CK), degree of pain and “muscle” blood flow rate (133Xenon washout technique). This was repeated in experiment II (exp. II) 6–12 months later in order to study reproducbility. In experiment III (exp. III), the normal fluctuations over 8 d of the seven parameters were measured, without intervention with eccentric exercise in 6 other subjects.

All subjects experienced pain, reaching a maximum 48 h after eccentric exercise in both exp. I and II. A systematic effect over time for CK (increasing 278% resp. 308%), muscle strength (decreasing more than 10%), PCr/Pi (decreasing 31% resp. 43%) and Pi/ATP (increasing 55% resp. 99%) was found in both exp. I and II (P<0.05), but not in exp. III. No significant difference was observed between exp. I and II for CK, blood‐flow rate, concentric muscle strength, PCr/Pi, Pi/ATP and PCr/ATP. It is concluded that pathophysiological alterations in m. quadriceps following eccentric exercise can be induced and can be reproduced after an interval of 6 months. Thus, this model can be used to study the effects of physiotherapy.
The effect of passive stretching on delayed onset muscle soreness, and other detrimental effects following eccentric exercise
Authors: Lund H. , Vestergaard‐Poulsen P. , Kanstrup I.‐L. , Sejrsen P.
Published: July 2010

The aim of this study was to measure if passive stretching would influence delayed onset muscle soreness (DOMS), dynamic muscle strength, plasma creatine kinase concentration (CK) and the ratio of phosphocreatine to inorganic phosphate (PCr/Pi) following eccentric exercise. Seven healthy untrained women, 28–46 years old, performed eccentric exercise with the right m. quadriceps in an isokinetic dynamometer (Biodex, angle velocity: 60°. s−1) until exhaustion, in two different experiments, with an interval of 13‐23 months. In both experiments the PCr/Pi ratio, dynamic muscle strength, CK and muscle pain were measured before the eccentric exercise (day 0) and the following 7 d. In the second experiment daily passive stretching (3 times of 30 s duration, with a pause of 30 s in between) of m. quadriceps was included in the protocol. The stretching was performed before and immediately after the eccentric exercise at day 0, and before measurements of the dependent variables daily for the following 7 d. The eccentric exercise alone led to significant decreases in PCr/Pi ratio (P<0.001) and muscle strength (P<0.001), and an increase in CK concentration (P<0.01). All subjects reported pain in the right m. quadriceps with a peak 48 h after exercise. There was no difference in the reported variables between experiments one and two. It is concluded that passive stretching did not have any significant influence on increased plasma‐ CK, muscle pain, muscle strength and the PCr/Pi ratio, indicating that passive stretching after eccentric exercise cannot prevent secondary pathological alterations.
Coronary heart disease risk factors in middle‐aged former top‐level athletes
Authors: Pihl E. , Jürimäe T. , Kaasik T.
Published: July 2010

A cross‐sectional study was conducted to determine the impact of previous athleticism on coronary heart disease (CHD) risk factors in 168 middle‐aged men and 147 middle‐aged women in Estonia. Participants were divided into four groups: physically active ex‐athletes (AA), sedentary ex‐athletes (SA), recreational exercisers (RE), and non‐exercisers (NE). The Sharkey's questionnaire was applied to determine the CHD risk factors, health habits, medical, safety, personal, psychological and women's risk factors scores. Anthropometric characteristics, resting systolic and diastolic blood pressure values (SBP, DBP), and physical working capacity (PWC170) were measured. Concentrations of total cholesterol (CHOL), high‐density lipoprotein cholesterol (HDL‐C), triacylglycerols (TG), and glucose were determined. Low‐density lipoprotein cholesterol (LDL‐C) and HDL‐C/CHOL ratio were computed. From the questionnaire results, significant differences in CHD risk scores in both sex groups in favour of AA and RE were found. DBP in men was significantly higher in SA, and SBP in women was significantly higher in NE in comparison with other groups. PWC170 and PWC170/kg was highest in AA and lowest in NE in both sex groups. There were no significant differences for blood biochemical parameters between women's groups. In men, AA had a lower CHOL level in comparison with SA and NE, and lower concentrations of TG and LDL‐C than other groups. AA and RE had a higher HDL‐C concentration and HDL‐C/CHOL ratio in comparison with the other groups. In conclusion, differences in CHD risk factors were related to current physical activity, and were more expressed in men than in women.
Surgical treatment of concomitant chronic ankle instability and longitudinal rupture of the peroneus brevis tendon
Authors: Karlsson J. , Brandsson S. , Kälebo P. , Eriksson B. I.
Published: July 2010

Chronic lateral ankle instability can be associated with a longitudinal rupture of the peroneus brevis tendon. Patients with these problems have atypical posterolateral or retromalleolar pain, as well as clinical signs of ligamentous instability. This injury is frequently concomitant with lateral ligament injuries and the injury mechanism is similar; however, the tendon rupture is often missed. Laxity or insufficiency of the superior peroneal retinaculum allows the anterior part of the peroneus brevis tendon to ride upon the sharp posterior fibular edge, resulting in a longitudinal rupture of the tendon. We report on the results after surgical treatment in nine patients (10 ankles) with combined instability of the lateral ankle ligaments and longitudinal rupture of the peroneus brevis tendon. All these patients underwent surgical repair of the peroneus tendon, reconstruction of the superior peroneal retinaculum, removal of the sharp posterior edge of the fibula and correction of the ligamentous instability of the anterior talofibular and calcaneofibular ligaments. One constant finding at surgery was a longitudinal intratendineal rupture of the peroneus brevis tendon combined with insufficiency of the superior peroneal retinaculum and insufficiency of the lateral ligaments. At follow‐up 3 (2–5) years postoperatively, the functional results were excellent or good in nine ankles and fair in one. All the patients with excellent or good results had resumed their preinjury activity level. We conclude that this lesion should be suspected in patients with lateral ligamentous instability, combined with retromalleolar pain. In these cases, it is important to address both the tendon rupture and the ligamentous insufficiency.
Salmeterol and physical performance at ‐15°C in hghly trained nonasthmatic cross‐country skiers
Authors: Sue‐Chu M. , Sandsund M. , Helgerud J. , Reinertsen R. E. , Bjermer L.
Published: July 2010

The aim of this double‐blind. placebo‐controlled, cross‐over study was to investigate possible improvement in physical performance at an ambient temperature of −15°C by an inhaled dose of 50 μg salmeterol in 8 highly trained nonasthmatic cross‐country skiers. FEV1 was measured before, during and after the treadmill exercise protocol, which consisted of a warm‐up run. runs of 10 min at 90%, and 5 min at 80%VO2max, followed by a timed run to exhaustion. Despite a significant improvement in FEV1, salmeterol did not have a beneficial effect on heart rate, blood lactate concentration, respiratory exchange ratio, oxygen uptake or minute ventilation during the exercise protocol. Running time to exhaustion was not significantly different from placebo. This lack of enhancement of exercise performance in healthy endurance athletes further supports the recent approval of salmeterol for prophylactic use by asthmatic athletes during training and competition.
Calf muscle atrophy and Achilles tendon healing following experimental tendon division and surgery in rats
Authors: Rantanen J. , Hurme T. , Kalimo H.
Published: July 2010

We used a rat model to study the effects of immobilization of the calf muscle‐tendon complex after an experimental Achilles tendon repair. Immobilizations of the complex in either a relaxed or tensioned position were compared by histochemical and morphometric analyses at the site of the tendon injury as well as in the gastrocnemius and soleus muscle bellies. The type of immobilization did not affect the healing of the tendon injury because no reruptures occurred in either of the treatment groups and the average tendon end‐to‐end distance did not differ between the groups. However, immobilization in a relaxed position led to a significantly more extensive fiber atrophy in the calf muscles. In clinical practice, these results suggest that rehabilitation after Achilles tendon surgery can be early and gradually tension‐ and load‐increasing without a significant increase in the risk of rerupture of the tendon.
Five‐year outcome of 13 patients with an initially undiagnosed anterior cruciate ligament rupture
Authors: Grøntvedt T. , Heir S. , Rossvoll I. , Engebretsen L.
Published: July 2010

We evaluated retrospectively the 5‐year outcome of 13 patients with an initially undiagnosed and thus untreated anterior cruciate ligament rupture. At follow‐up, these patients experienced decreased knee function and moderate to severe knee instability. They had attempted to reduce their discomfort by decreasing their activity level during the follow‐up period. Immediately after the 5‐year examination, 6 of the patients decided to have a late reconstruction of the ruptured anterior cruciate ligament. These results agree with previous reports of the natural course of anterior cruciate ligament ruptures.
Factors explaining the physical activity of young adults: the importance of early socialization
Authors: Yang X. , Telama R. , Leino M. , Viikari J.
Published: July 2010

As a part of the large project Cardiovascular Risk in Young Finns, the purpose of the present study was to examine how adult physical activity is influenced by early physical activity and current social and health‐related factors. A total of 2411 children and adolescents aged 9, 12, 15 and 18 years were randomly selected from five university towns and their rural surroundings in 1980. They were followed up for 12 years by means of questionnaires. In 1992 they were 21, 24, 27 and 30 years old. The results showed that early physical activity and current social and health‐related behaviours were significantly related to the level of adult physical activity. Multivariable analyses indicated that early physical activity, in particular, was the best predictor of adult physical activity in all groups, with the exception of the 21‐year‐old women. The social and health‐related factors such as occupation, employment status and smoking also predicted physical activity in some age‐gender groups.
Anterior tibial translation during eccentric, isokinetic quadriceps work in healthy subjects
Authors: Kvisti J. , Gillquist J.
Published: July 2010

The effect of increasing isokinetic, eccentric quadriceps torques on sagittal translation of the tibia was examined in six healthy volunteers and compared to the translation at 20° of knee flexion during a drawer test with 90 N force. The tibial translation increased in a linear fashion with a mean of 0.5 mm per 20% torque increase. In 20° of knee flexion, 10% of eccentric quadriceps peak torque consumed 80% of the anterior tibial translation induced by the 90 N Lachman test while eccentric quadriceps peak torque utilized 100% of the translation at the same test. The in vivo relation between muscle force and tibial translation is of importance in the treatment of patients with injury to the cruciate ligaments. The results indicate that an already low eccentric quadriceps torque causes a tibial translation that reaches the limit of the passive knee joint displacement where strain is assumed to develop in the anterior cruciate ligament. Already low eccentric quadriceps torque levels may therefore be harmful during rehabilitation after anterior cruciate ligament surgery.
Neck muscle ultrasonography of male weight‐lifters, wrestlers and controls
Authors: Rezasoltani A. , Mälkiä E. , Vihko V.
Published: July 2010

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.
Predicting physical activity intentions using a goal perspectives approach: a study of Finnish youth
Authors: Lintunen T. , Valkonen A. , Leskinen E. , Biddle S. J. H.
Published: July 2010

Physical activity intentions were studied in 12‐ to 16‐year‐old Finnish girls (n= 186) and boys (n= 215). Theoretical predictions were used to establish a model that was then tested separately for each sex using path analysis. Firstly, it was hypothesised that malleable conceptions of the nature of sport ability positively influence enjoyment in physical activity and intentions to participate in physical activity, mediated by a task‐oriented achievement goal independent of variations in perceptions of competence. Secondly, it was hypothesised that fixed conceptions of the nature of ability decrease enjoyment in physical activity and intentions to participate, mediated by an ego‐oriented achievement goal and by perceived competence. The modified models were shown to fit the data. Overall, the results showed that 63% (boys) and 45% (girls) of the variance in intentions was explained by the model. The motivational importance of task orientation and. among the boys, perceived physical competence was confirmed with their direct prediction of intentions.
Goal orientations, beliefs about success, and performance improvement among young elite Dutch soccer players
Authors: Van‐Yperen N. W. , Duda J. L.
Published: July 2010

Extending past work testing goal perspective theory in sport, one purpose of this study was to examine, via a longitudinal design, the relationship of goal orientations to the beliefs about the causes of success in the case of elite male Dutch soccer players. A second purpose was to determine the relationship of goals and beliefs to ratings of performance. Seventy‐five male pupils representing five teams from an internationally renowned soccer school in The Netherlands completed the TEOSQ and a measure of their perceptions of the determinants of success in soccer at the onset and conclusion of one season. Assessments of the coaches' appraisal and athletes' self‐reported performance in soccer were carried out at the same time. In line with other studies, a positive association between ego orientation and the belief that ability or innate talent are determinants of success was revealed. Task orientation was linked to the beliefs that effort, team play, and parental support contribute to achievement in soccer. An increase in skilled performance over the season (as appraised by the coach) corresponded to a stronger task orientation and the beliefs that soccer success stems from hard work and having supportive parents.
Motivational climate and goal orientations as predictors of perceptions of improvement, satisfaction and coach ratings among tennis players
Authors: Balaguer I. , Duda J. L. , Crespo M.
Published: July 2010

One purpose of this work was to study the relationship of goal orientations and the perceived motivational climate created by the coach in relation to 219 competitive Spanish tennis players': a) perceived improvement in different facets of the game, b) satisfaction with their competitive results, overall level of play, and coach, and c) ratings of their coach. The second purpose was to examine whether the dependent variables were best predicted by the perceived situationally emphasized goal structure created by the coach and/or the athletes' dispositional goal perspective. Intermediate (N=70), advanced (N=124), and professional (N=25) level players completed Spanish versions of the TEOSQ and the PMCSQ‐2 and items assessing perceived improvement specific to tennis, satisfaction and coach ratings. The results were consistent with the tenets of goal perspective theory and provide further support for the promotion of a task‐involving atmosphere in sport.
Meniscal substitutes – human experience
Authors: Goble E. M. , Kohn D. , Verdonk R. , Kane S. M.
Published: July 2010

A number of clinical series have described the effect of meniscus allograft replacement in humans. The general indication has been disabling pain following loss of a meniscus in a skeletally mature individual. Overall, healing of the graft to the capsule occurs in up to 80% of all transplants. Revascularization and cell repopulation is found in all grafts but is highly variable. The risk for graft failure seems to be greater with irradiated grafts and in patients with grade III or IV osteoarthritic changes. In most series, patients experienced a decrease in pain and an increase in activity level postoperatively. In many series, concominant surgery (cruciate ligament reconstruction or osteotomy) had been performed. Meniscus replacement with frozen or cryopreserved allografts seems to give the most promising short‐term results in patients with post‐meniscectomy pain. Controlled, randomized prospective studies are needed to confirm a long‐term benefit and better define transplantation indications.

Viable meniscus allografts seem to survive transplantation, as donor cells were found in the graft after 2 years. Clinically, pain was reduced and activity increased following transplantation, but after 4 years some of these gains were lost. There was no correlation between postoperative findings on MRI and clinical outcome.

Meniscal replacement with a quadriceps tendon autograft in humans resulted in pain reduction, but at second‐look arthroscopy, only 2 of 9 tendon autografts looked like a meniscus. Six were in position but still looked like tendons. Total medial meniscus replacement by quadriceps tendon autrograft is still an experimental procedure.

There is no proof at present that meniscal substitutes (meniscus allografts or tendon autografts) in humans can protect the hyaline cartilage of the knee from the degeneration, following loss of a meniscus. There is some evidence in animal experiments that under circumstances not yet exactly known, a meniscus substitute can have a protective effect on articular cartilage. Three factors have been identified that prevent proper meniscal function: poor fixation of the meniscal horns, no contact of the graft with the articulating surfaces under load and incorrect positioning of the horns. Meniscal allograft transplantation sensitizes humoral and cell mediated immune systems. Bone plugs attached to meniscal allograft tissue may increase cell surface antigenicity. Deep freezing and especially freeze drying of meniscal tissue decreases host immunogenicity. Cryopreservation maintains the content of donor HLA encoded antigens and is likely more sensitizing to the host. The clinical importance of immune responses to meniscal allografts is not known, but it has not been shown to result in graft failure or rejection. Prospective studies are needed.
Fat in the Fire? Science, the News Media, and the “Obesity Epidemic”2
Authors: Saguy Abigail C. , Almeling Rene
Published: July 2010

In recent years, the “obesity epidemic” has emerged as a putative public health crisis. This article examines the interconnected role of medical science and news reporting in shaping the way obesity is framed as a social problem. Drawing on a sample of scientific publications on weight and health, and press releases and news reporting on these publications, we compare and contrast social problem frames in medical science and news reporting. We find substantial overlap in science and news reporting, but the news media do dramatize more than the studies on which they are reporting and are more likely than the original science to highlight individual blame for weight. This is partly due to the news media’s tendency to report more heavily on the most alarmist and individual‐blaming scientific studies. We find some evidence that press releases also shape which articles receive media coverage and how they are framed.
Low‐intensity training dissociates metabolic from aerobic fitness
Authors: Helge J. W. , Damsgaard R. , Overgaard K. , Andersen J. L. , Donsmark M. , Dyrskog S. E. , Hermansen K. , Saltin B. , Daugaard J. R.
Published: July 2010

This study investigated the effect of prolonged whole‐body low‐intensity exercise on blood lipids, skeletal muscle adaptations and aerobic fitness. Seven male subjects completed a 32‐day crossing of the Greenland icecap on cross‐country skies and before and after this arm or leg cranking was performed on two separate days and biopsies were obtained from arm and leg muscle, and venous blood was sampled.

During the crossing, subjects skied for 342±42 min/day and body mass was decreased by 7.1±0.7 kg. Peak leg oxygen uptake (4.6±0.2 L/min) was decreased (P<0.05) by 7% whereas peak arm oxygen uptake (3.0±0.2 L/min) remained unchanged. Total and low‐density lipoprotein cholesterol (5.0±0.2 and 3.20.2 mmol/L) were decreased by 8% and 20%, respectively. Muscle β‐hydroxy‐acyl‐CoA dehydrogenase activity was increased with 22% in arm (P=0.08) and remained unchanged in leg muscle. Hormone sensitive lipase activity was similar in arm and leg muscle prior to the expedition and was not significantly affected by the crossing.

In conclusion, an improved blood lipid profile and thus metabolic fitness was present after prolonged low‐intensity training and this occurred in spite of a decreased aerobic fitness and an unchanged arm and leg muscle hormone‐sensitive lipase activity.
Rate of reduction of heart rate variability during exercise as an index of physical work capacity
Authors: Lewis M. J. , Kingsley M. , Short A. L. , Simpson K.
Published: July 2010

Breathing rates during physical exercise suggest that, during these conditions, the high‐frequency (HF) bandwidth of heart rate variability (HRV) analysis should be extended beyond conventional guidelines. However, there has been little investigation of the most appropriate choice of HF bandwidth during exercise. HRV analysis was performed in 10 males and six females during progressive bicycle exercise. Cardiac cycle (RR) interval and breath‐by‐breath respiratory data were simultaneously recorded. HRV powers were determined for the band‐limited ranges 0.04–0.15 Hz [low‐frequency (LF)], 0.15–0.4 Hz (HF0.4) and 0.15−bf Hz (HFbf, where bf represents maximum breathing frequency). Mono‐exponential functions described the relationship between HRV and work rate for each bandwidth (r=0.92–0.95) and were used to calculate the “HRV decay constant” (work rate associated with a 50% reduction in HRV power). The HRV decay constants for each bandwidth were linearly related to maximal work rate (r>0.71; P<0.001) and were substantially greater in males than in females (P<0.001). There was a significant difference between the HRV decay constants for HF0.4 and HFbf (P<0.005) in both genders. The HRV decay constants for the LF and HFbf bandwidths appear to provide an indication of work capacity from submaximal exercise, without prior assumption regarding heart rate and its relationship with work rate.
RETRACTED: Effects of strength and endurance training on antioxidant enzyme gene expression and activity in middle‐aged men
Authors: García‐López D. , Häkkinen K. , Cuevas M. J. , Lima E. , Kauhanen A. , Mattila M. , Sillanpää E. , Ahtiainen J. P. , Karavirta L. , Almar M. , González‐Gallego J.
Published: July 2010

This study was aimed at investigating the effects of a 21‐week period of progressive strength or endurance training on peripheral blood mononuclear cells (PBMC) antioxidant enzyme gene expression and activity in healthy middle‐aged untrained men. Strength (n=11) and endurance (n=12) training were performed twice a week, including resistance exercises to activate all the main muscle groups or cycle‐ergometer pedaling, respectively. mRNA levels of catalase, glutathione peroxidase (GPx), mitochondrial superoxide dismutase (MnSOD) and cytosolic superoxide dismutase (CuZnSOD) were increased after 21 weeks of strength training, while endurance training induced significant changes only in MnSOD and GPx mRNA levels. CuZnSOD protein content was significantly increased only in strength‐trained subjects. The program of strength or endurance exercise training had no significant effects on the activity of any of the antioxidant enzymes. In conclusion, in a middle‐aged population, 21 weeks of strength or endurance training was a sufficient stimulus to up‐regulate mRNA levels of PBMC antioxidant enzymes, the strength training being a more optimal stimulus. However, the discrepancies between enzyme protein and mRNA levels suggest that the present systematic strength or endurance training period had no beneficial effects on enzymatic antioxidant defense mechanisms in previously untrained middle‐aged men.
Tracking of objectively measured physical activity from childhood to adolescence: The European youth heart study
Authors: Kristensen P. L. , Møller N. C. , Korsholm L. , Wedderkopp N. , Andersen L. B. , Froberg K.
Published: July 2010

A number of studies have investigated tracking of physical activity from childhood to adolescence and, in general, these studies have been based on methods with some degree of subjectivity (e.g., questionnaires). The aim of the present study was to evaluate tracking of physical activity from childhood to adolescence using accelerometry, taking into account major sources of variation in physical activity. Both a crude and an adjusted model was fitted, and, in the adjusted model, analyses were corrected for seasonal variation, within‐week variation, activity registration during night time sleep, within instrumental measurement error, and day‐to‐day variation in physical activity. In all, 208 subjects were included in the crude analyses. Stability coefficients estimated from the crude model were low (i.e., 0.18 and 0.19 for boys and girls, respectively) and only borderline significant. However, in the adjusted model highly significant stability coefficients of 0.53 and 0.48 for boys and girls, respectively, were observed. It was concluded that physical activity behavior tends to track moderately from childhood to adolescence.
Body mass index‐independent effect of fitness and physical activity for all‐cause mortality
Authors: Pedersen B. K.
Published: July 2010

Both obesity and physical inactivity are associated with chronic disease and premature mortality. A review of the literature has shown that both objectively measured level of physical fitness and self‐reported physical activity have a prognostic value for all‐cause mortality, independently of body mass index. Furthermore, there is evidence for a dose–response effect of physical activity. In conclusion, regular exercise has health‐promoting effects, which are beyond its effect on weight control.
Interleukin‐6 and its mRNA responses in exercise and recovery: relationship to muscle glycogen
Authors: Gusba J. E. , Wilson R. J. , Robinson D. L. , Graham T. E.
Published: July 2010

Increases in circulating interleukin‐6 (IL‐6) during exhaustive exercise have been suggested to be related to declining muscle glycogen. We addressed two hypotheses: (a) exhaustive exercise on two occasions will result in similar decreases in glycogen and increases in circulating IL‐6 and its muscle mRNA; (b) increasing the rate of glycogen restoration via high‐carbohydrate feeding in recovery will be associated with more rapid declines in muscle mRNA and circulating IL‐6. Ten male subjects (22.6±0.8 year) cycled to exhaustion (65% VO2 max) on two occasions (117.8±2.9 min). Carbohydrate (1 g/kg bw) or water was ingested at exhaustion, 60, 120, 180, and 240 min post‐exercise. Muscle biopsies were taken at rest, exhaustion, 30, 60, 120 and 300 min of recovery. Exercise resulted in a 14.5‐fold increase (P<0.05) in IL‐6 mRNA, 14.4‐fold increase (P<0.05) in circulating IL‐6, and a 80% decrease (P<0.05) in muscle glycogen from rest. The decline in glycogen was not correlated with the increase in IL‐6 or IL‐6 mRNA. During recovery, circulating IL‐6 and its muscle mRNA decreased similarly in both trials; however, glycogen increased 150% (P<0.05) and 40% in the carbohydrate and water trials, respectively. Therefore, the declining IL‐6 mRNA and IL‐6 plasma concentrations during recovery were not related to carbohydrate availability or changes in glycogen.
Load‐specific differences in the structure of femoral neck and tibia between world‐class moguls skiers and slalom skiers
Authors: Nikander R. , Sievänen H. , Heinonen A. , Karstila T. , Kannus P.
Published: July 2010

Bone structure of weight‐bearing proximal femur and tibia was examined among the Finnish world‐class moguls skiers and slalom skiers. We hypothesized that these bones, during typical sport‐specific performance, had been subjected not only to extreme loading but also to distinct loading in terms of rate and primary direction. Bone [dual‐energy X‐ray absorptiometry (DXA), peripheral quantitative computed tomography (pQCT), magnetic resonance imaging] and muscle performance data of the lower extremities were obtained from the five Finnish male moguls skiers and six slalom skiers competing at the World Cup level. Data (DXA, pQCT) from 12 age‐ and weight‐matched normally active men were used for comparison. The ANCOVA with body height as a covariate was used for statistical analysis. The weight‐bearing bones of the athletes were 10–60% stronger than those of the normally active men. Compared with the moguls skiers, the slalom skiers showed an average 43% thicker anterior cortex at the narrowest region of the femoral neck. This study suggests that the bone structure at skiers' heavily loaded lower extremities was very robust. A specific finding was the thick anterior cortex of the femoral neck among the slalom skiers. Apparently, the predominant loading type had modulated the site‐specific skeletal response to physical exertion.
Is there an association between PPARGC1A genotypes and endurance capacity in Chinese men?
Authors: He Z. , Hu Y. , Feng L. , Bao D. , Wang L. , Li Y. , Wang J. , Liu G. , Xi Y. , Wen L. , Lucia A.
Published: July 2010

Our purpose was to determine the possible association between genotypes of three polymorphisms (Gly482Ser, Thr394Thr and A2962G) of the peroxisome proliferator‐activated receptor γ coactivator 1α (PPARGC1A) gene, on one hand, and both the pre‐ (baseline) and post‐training levels of maximal (i.e., maximal oxygen uptake [VO2max]) and submaximal human endurance capacity (i.e., running economy [RE]). We studied 102 young males (physically active, non‐athletes; age: 19±1 yrs) from Northern China (of Han origin) who underwent a 18‐week endurance training (running) program and were tested on a treadmill (for VO2max and RE determination) before and after training. None of the VO2max and RE related traits were associated with the Gly482Ser and Thr394Thr polymorphisms at baseline or after training. The A2962G polymorphism was however associated with VO2max at baseline, as carriers of the G allele (AG+GG genotypes; n=49) had higher levels of VO2max than the AA group (n=53) (58.2±4.3 vs 56.3±3.9 mL/kg/min; P=0.017). Our results do not support previous data on Caucasians showing an association between the Gly482Ser variant and VO2max but suggest the potential role of another polymorphism (A2962G) to explain individual VO2max differences in Chinese men.
Prevalence and incidence of lower extremity injuries in male marathon runners
Authors: Van Middelkoop M. , Kolkman J. , Van Ochten J. , Bierma‐Zeinstra S. M. A. , Koes B.
Published: July 2010

The aim of this study is to describe the prevalence and incidence of lower extremity injuries occurring before and during the Rotterdam marathon, and to evaluate the impact of the injuries. A cohort study was compiled of recreational male participants in the 2005 Rotterdam marathon. Demographic data and information on previous injuries were obtained from participants using a baseline questionnaire. Information on injuries sustained shortly before or during the marathon was obtained from a post‐race questionnaire. Seven hundred and twenty‐five (48.3%) participants returned the baseline questionnaire. The 1‐year prevalence of running injuries was 54.8%. In the post‐race questionnaire, 15.6% of all respondents reported at least one new lower extremity injury in the month preceding the Rotterdam marathon. The incidence of lower extremity injuries occurring during the marathon was 18.2%; most of these injuries occurred in the calf, knee and thigh. Immediately after the marathon the median score of pain intensity at rest was 2 points vs 4.5 points during physical exercise. Hence we can conclude that running injuries are very common among recreational male marathon runners. However, the pain severity and consequences for work and daily activities seem to be relatively low 1 week after the marathon.
Perceived barriers to physical activity across Norwegian adult age groups, gender and stages of change
Authors: Sørensen M. , Gill D. L.
Published: July 2010

This study investigated differences in the type of and number of perceived barriers to engagement in physical activity experienced by adult women and men in the same geographical area, the relationship between the experienced barriers and stages of change in relation to exercise behavior, and identified barriers related to reported engagement in leisure‐time physical activity. Data were obtained from a population study by the National Institute of Public Health in two counties during 2000–2001. The sample consisted of 2709 females and 2212 men in the age groups 75, 60, 45, 40 and 30 years. Questionnaires measured barriers to engagement in physical activity, engagement in physical activity and readiness for engaging in physical activity (stages of change). Multivariate analyses of variance demonstrated significant age and gender differences in the perceptions of barriers at the various stages of change. The logistic regressions [estimated odds ratios (OR)] demonstrated that low scores for affective/cognitive and practical barriers were significantly associated with higher OR for engagement in physical activity for women, and low‐priority barriers and lower age were associated with higher OR for being physically active for men. The information from this study should be valuable for designing and tailoring both motivational strategies and interventions to fit targeted groups.
Preventing injuries in female youth football – a cluster‐randomized controlled trial
Authors: Steffen K. , Myklebust G. , Olsen O. E. , Holme I. , Bahr R.
Published: July 2010

A set of exercises – the “11”– have been selected to prevent football injuries. The purpose of this cluster‐randomized controlled trial was to investigate the effect of the “11” on injury risk in female youth football. Teams were randomized to an intervention (n=59 teams, 1091 players) or a control group (n=54 teams, 1001 players). The intervention group was taught the “11,” exercises for core stability, lower extremity strength, neuromuscular control and agility, to be used as a 15‐min warm‐up program for football training over an 8‐month season. A total of 396 players (20%) sustained 483 injuries. No difference was observed in the overall injury rate between the intervention (3.6 injuries/1000 h, confidence interval (CI) 3.2–4.1) and control group (3.7, CI 3.2–4.1; RR=1.0, CI 0.8–1.2; P=0.94) nor in the incidence for any type of injury. During the first 4 months of the season, the training program was used during 60% of the football training sessions, but only 14 out of 58 intervention teams completed more than 20 prevention training sessions. In conclusion, we observed no effect of the injury prevention program on the injury rate, most likely because the compliance with the program was low.
Morphological comparison of different protocols of skeletal muscle remobilization in rats after hindlimb suspension
Authors: Cornachione A. , Cação‐Benedini L. O. , Shimano M. M. , Volpon J. B. , Martinez E. Z. , Mattiello‐Sverzut A. C.
Published: July 2010

The aim of this study was to evaluate and compare the efficacy of different remobilization protocols in different skeletal muscles considering the changes induced by hindlimb suspension of the tail. Thirty‐six female Wistar rats were divided into six groups: control I, control II, suspended, suspended free, suspended trained on a declined treadmill and suspended trained on a flat treadmill. Fragments of soleus and tibialis anterior (TA) muscle were frozen and processed by different histochemical methods. The suspended soleus showed a significant increase in the proportional number of intermediate/hybrid fibers and a decrease in the number of type I fibers. Some of these changes proved to be reversible after remobilization. The three remobilization programs led to the recovery of both the proportional number of fibers and their size. The TA muscle presented a significant increase in the number and size of type I fibers and a cell size reduction of type IIB fibers, which were recovered after training on a declined treadmill and free movement. Especially regarding the soleus, the present findings indicate that, among the protocols, training on a declined treadmill was found to induce changes of a more regenerative nature, seemingly indicating a better tissue restructuring after the suspension procedure.
Cycling to work: influence on indexes of health in untrained men and women in Flanders. Coronary heart disease and quality of life
Authors: De Geus B. , Van Hoof E. , Aerts I. , Meeusen R.
Published: July 2010

The purpose of this study was to examine if a 1‐year lifestyle intervention study (cycling to work) has an influence on coronary heart disease (CHD) risk factors and health‐related quality of life, in previously untrained healthy adults. Healthy, untrained men and women, who did not cycle to work, participated in an intervention study. Sixty‐five subjects (intervention group: IG) were asked to cycle to work at least 3 times a week and 15 controls (CG) were asked not to change their living habits. All measurements were performed on 3 consecutive occasions, with 6 months in between. Physical performance, venous blood samples, blood pressure (BP), and the SF‐36 Health Status Survey were assessed. Cycling characteristics and leisure‐time physical activities were reported in a dairy. Total cholesterol (TC), LDL, TC/HDL and diastolic BP decreased and HDL increased significantly in the IG. TC and LDL decreased significantly in the CG. Vitality for the total group and physical functioning for women significantly changed over time between IG and CG in the first 6 months. These results show that cycling to work has a positive influence on CHD risk factors and is likely to improve the health‐related quality of life in previously untrained healthy adults.
Daily physical activity related to aerobic fitness and body fat in an urban sample of children
Authors: Dencker M. , Thorsson O. , Karlsson M. K. , Lindén C. , Wollmer P. , Andersen L. B.
Published: July 2010

This study evaluates associations between objectively measured daily physical activity vs aerobic fitness and body fat in children aged 8–11 years. A cross‐sectional study of 225 children aged 7.9–11.1 years was performed. Abdominal fat mass (AFM) and total body fat (TBF) were quantified by dual‐energy x‐ray absorptiometry. TBF was calculated as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. Aerobic fitness was measured by indirect calorimetry during a maximal cycle ergometer exercise test. Daily physical activity was assessed by accelerometers for 4 days and daily accumulation of moderate‐to‐vigorous and vigorous activity was calculated. Significant relationships (P<0.05) existed for vigorous activity vs ln BF% (r=−0.40), ln AFM (r=−0.35), TBF/AFM (r=−0.22) and aerobic fitness (r=0.38), whereas moderate‐to‐vigorous activity displayed weaker relationships (−0.22, −0.18, −0.12 NS, and 0.25). Multiple regression analyses with inclusion of possible confounders concluded that vigorous activity was independently related to aerobic fitness and ln BF% or ln AFM. Moderate‐to‐vigorous activity was only independently related to aerobic fitness. In this population, low daily accumulation of vigorous activity was, already in children aged 8–11 years, associated with more body fat and lower aerobic fitness. A similar relation was not found for daily accumulation of moderate‐to‐vigorous activity.