bluuebunny/crossref_metadata_2025 huggingface dataset:
Biogeochemical Proxies of Anthropic Impact in Mediterranean Forest Soils
Authors: Tinoco P. , Piedra Buena A. , Zancada M. C. , Sanz J. , Almendros G.
Published: July 2010

Quantitative changes in soil organic matter (SOM) from undisturbed Mediterranean forests and neighbouring deforested sites were assessed by analysing soil lipids and humic acids (HAs), in total studying 80 variables. Changes in the composition of free lipids reflected vegetation types, whereas HAs analysed by visible and13C NMR spectroscopy, sodium perborate degradation and Curie‐point pyrolysis indicated the extent of structural alteration of lignin in soil. The molecular fractions released by degradation techniques applied to HAs showed that demethoxylation and oxidation were associated with the removal of forest vegetation, and the aromatic compounds consisted mainly of methoxyphenols and benzenecarboxylic acids. Decreased concentration of alkanes and increased amounts of alcohols were observed after removal of forests. The chain lengths of alkyl compounds also tended to decrease. In forest soil, there was a series of diterpene resin acids, whereas in pasture soil steroids from animal origin and a root‐derived triterpenoids with friedelan structure were found. In relation to the total quantity and quality of soil C, the overall chemical descriptors indicated that clearing and cultivation (semiarid cereal fields) lead to intense mineralization of SOM (mainly particulate, free organic matter) but the residual humic substances have enhanced maturity in terms of structural condensation and potential resilience. Conversely, the cleared forest soil under pasture had a comparatively higher potential for C sequestration, but the HA characteristics suggested selective preservation of plant biomacromolecules directly incorporated as underground biomass.
A Multiscale Network Analysis of Protected‐Area Connectivity for Mammals in the United States
Authors: MINOR EMILY S. , LOOKINGBILL TODD R.
Published: July 2010

Abstract:  Protected areas must be close, or connected, enough to allow for the preservation of large‐scale ecological and evolutionary processes, such as gene flow, migration, and range shifts in response to climate change. Nevertheless, it is unknown whether the network of protected areas in the United States is connected in a way that will preserve biodiversity over large temporal and spatial scales. It is also unclear whether protected‐area networks that function for larger species will function for smaller species. We assessed the connectivity of protected areas in the three largest biomes in the United States. With methods from graph theory—a branch of mathematics that deals with connectivity and flow—we identified and measured networks of protected areas for three different groups of mammals. We also examined the value of using umbrella species (typically large‐bodied, far‐ranging mammals) in designing large‐scale networks of protected areas. Although the total amount of protected land varied greatly among biomes in the United States, overall connectivity did not. In general, protected‐area networks were well connected for large mammals but not for smaller mammals. Additionally, it was not possible to predict connectivity for small mammals on the basis of connectivity for large mammals, which suggests the umbrella species approach may not be an appropriate design strategy for conservation networks intended to protect many species. Our findings indicate different strategies should be used to increase the likelihood of persistence for different groups of species. Strategic linkages of existing lands should be a conservation priority for smaller mammals, whereas conservation of larger mammals would benefit most from the protection of more land.
Use of Acoustic Tools to Reveal Otherwise Cryptic Responses of Forest Elephants to Oil Exploration
Authors: WREGE PETER H. , ROWLAND ELIZABETH D. , THOMPSON BRUCE G. , BATRUCH NIKOLAS
Published: July 2010

Abstract: Most evaluations of the effects of human activities on wild animals have focused on estimating changes in abundance and distribution of threatened species; however, ecosystem disturbances also affect aspects of animal behavior such as short‐term movement, activity budgets, and reproduction. It may take a long time for changes in behavior to manifest as changes in abundance or distribution. Therefore, it is important to have methods with which to detect short‐term behavioral responses to human activity. We used continuous acoustic and seismic monitoring to evaluate the short‐term effects of seismic prospecting for oil on forest elephants (Loxodonta cyclotis) in Gabon, Central Africa. We monitored changes in elephant abundance and activity as a function of the frequency and intensity of acoustic and seismic signals from dynamite detonation and human activity. Elephants did not flee the area being explored; the relative number of elephants increased in a seasonal pattern typical of elsewhere in the ecosystem. In the exploration area, however, they became more nocturnal. Neither the intensity nor the frequency of dynamite blasts affected the frequency of calling or the daily pattern of elephant activity. Nevertheless, the shift of activity to nocturnal hours became more pronounced as human activity neared each monitored area of forest. This change in activity pattern and its likely causes would not have been detected through standard monitoring methods, which are not sensitive to behavioral changes over short time scales (e.g., dung transects, point counts) or cover a limited area (e.g., camera traps). Simultaneous acoustic monitoring of animal communication, human, and environmental sounds allows the documentation of short‐term behavioral changes in response to human disturbance.
High‐Frequency Characterization of Porous Low‐Temperature Cofired Ceramics Substrates
Authors: Bittner Achim , Seidel Helmut , Schmid Ulrich
Published: July 2010

In this work, the permittivity of porous low‐temperature cofired ceramics (LTCC) DP 951 is measured and evaluated. Porosification is performed at originally dense LTCC substrates in the fired state by a wet chemical etching procedure using hot phosphoric acid. Choosing this approach, areas with tailored permittivity can be generated in one single LTCC layer. The etch time and the bath temperature precisely control the penetration, and hence, the porosification depth. Therefore, the decrease in dielectric constant of the LTCC substrate can be correlated to the thickness of the porous layer. The dielectric constant is measured using a ring resonator in the microstrip configuration. From the resonances occurring in the transmission S‐parameter |S21| spectrum between 1 and 10 GHz, the relative dielectric constant can be determined. Using 820‐μm‐thick substrates, a relatively low reduction from ɛr=7.8 to 6.45 is achieved when a porosification depth of about 35 μm is reached. Applying a fitting procedure, the dielectric constant of the pure porous layer is deduced to ɛr=2.3. Based on numerical simulations, the effective dielectric constant for a 100‐μm‐thick glass–ceramic layer, which is modified to a depth of 35 μm is calculated to 5.2, whereas the thickness represents a lower limit for commercially available tapes being typically implemented into the fabrication process of monolithic LTCC systems with integrated metallization planes. Compared with commercially available low‐K LTCC materials, this value is lower than all other commonly used tape systems.
A Simple Oxidation Route to Prepare Pseudobrookite from Panzhihua Raw Ilmenite
Authors: Chen Xi , Deng Jinxia , Yu Ranbo , Chen Jun , Hu Penghao , Xing Xianran
Published: July 2010

A simple oxidation route to prepare pseudobrookite from Panzhihua raw ilmenite was developed. By oxidizing ilmenite concentrate in air for 3 h at 1473 K, a pure pseudobrookite was achieved. The X‐ray diffraction studies showed a possible sequence of the phase evolution with temperature, FeTiO3→FeTiO3+Fe2O3+TiO2→Fe2O3+TiO2+Fe2Ti3O9→Fe2O3+TiO2+Fe2TiO5→Fe2TiO5. The sluggish formation reaction of the target product was ascribed to the low heat treatment temperature. During the phase transformation, the extra Ti atoms from FeTiO3 accommodate into the 4c and 8f sites to form the solid solution (Fe,Ti)2TiO5. AC susceptibility determinations indicated that the as‐prepared pseudobrookite was an antiferromagnetic compound and performed the typical anisotropic spin glass behaviors. The decreased phase transition temperature of the prepared pseudobrookite from order to disorder meant a high disorder degree. This oxidation route might be useful to the comprehensive utilization of raw ilmenite, especially for Panzhihua ilmenite in Pan‐Xi region of China.
Role of Mobile Cations on Microplasticity in Alumino‐Phosphate Glasses
Authors: Faivre Annelise , Despetis Florence , Guillaume Florie , Solignac Pierre , Ramonda Michel
Published: July 2010

Room‐temperature microplastic phenomena in oxide glasses are attributed to the combined effects of densification and shear flow, the origin of which, however, remains speculative. Using atomic force microscopy imaging to analyze the imprint topology created by microindentation in mixed alkali alumino‐phosphate glasses, we show that the amount of matter displaced at the surface is correlated with the alkali mobility. These results lead to the conclusion that mobile alkali assists shear flow processes produced by indentation at room temperature and that these processes correspond to plastic rather than viscous flow.
Fatigue effects of marathon running on neuromuscular performance
Authors: Nicol C. , Komi P. V. , Marconnet P.
Published: July 2010

The influence of an individual marathon race was investigated among 7 subjects who performed 2 types of unilateral isometric strength tests before and after the race. The tests included maximal isometric voluntary actions (MVA) of the knee extensor muscles and isometric endurance of 60% of pre‐marathon MVA. The results showed dramatic reductions of the maximal isometric torque (26 ± 14%) and endurance time (39 ± 9%). Maximal integrated electromyographic activity (IEMG) of the vastus medialis muscle decreased by 36 ± 26% and that of the vastus lateralis muscle by 42 ± 25%. In the submaximal endurance test, the post‐marathon isometric knee extension started at a higher level of IEMG and lower mean power frequency (MPF) for 6 of 7 subjects. These data suggest that the repeated stretch‐shortening cycles during the marathon race affected the force production by reducing neural input to the muscles and deteriorating the efficiency of the contractile mechanism.
Changes of polymorphonuclear granulocyte migration and lymphocyte proliferative responses in elite runners undergoing intense exercise
Authors: Espersen G. T. , Toft E. , Ernst E. , Kaalund S. , Grunnet N.
Published: July 2010

The immunoregulatory effects of intense exercise were examined measuring polymorphonuclear granulocyte (PMN) migration under agarose, lymphocyte proliferative responses after mitogen stimulation (phytohemagglutinin P, concanavalin A and pokeweed mitogen) and complement activation (C3 conversion) in the peripheral blood of elite runners undergoing maximal exertion. Eleven elite middle‐ and long‐distance runners were tested in a 5‐km race on a running track. PMN migration activity towards autologous serum and FMLP as chemoattractants both increased after intense physical activity. The lymphocytes showed increased proliferative responses to the mitogen stimulation 2 h after the run compared with pre‐exercise values, and normalized activity after 24 h. The total number of lymphocytes in the peripheral blood markedly decreased 2 h after the run and the number of leukocytes increased. A tendency to a decrease in complement C3 conversion‐was observed after the run, but within the estimated normal area. Our findings suggest that intense physical activity influences the cellular immune system.
Effects of marathon fatigue on running kinematics and economy
Authors: Nicol C. , Komi P. V. , Marconnet P.
Published: July 2010

The influence of marathon fatigue on both running kinematics and economy was investigated with 8 subjects. The measurements included a treadmill test at 3 steady submaximal speeds performed before and after the marathon. One complete left leg cycle was videotaped at 100 Hz from the left side at each speed. The analysis included contact time (braking and push‐off) and flight time as well as displacements and angular velocities of the left hip and knee. This analysis was complemented by the measurements of the electromyographic (EMG) activity of the gastrocnemius muscle at each running velocity, and energy expenditure (Ė) of the last 30 s at the 2 slowest speeds. The results revealed significant increases of Ė at these 2 speeds, but the changes were not related to kinematic changes, which were greatly individual. However, the relative duration of the push‐off phase was significantly increased at the 2 slowest speeds, and the gastrocnemius muscle presented higher integrated EMG values in the respective braking (NS) and push‐off phases at the 2 fastest speeds. This might indicate a loss of tolerance to impact during the belt contact. The results failed, however, to demonstrate that running kinematics and running economy are interrelated when fatigue progresses. It is also possible that observed kinematic changes might reflect some adaptation to fatigue more than real failure to compensate for it.
Effects of training at simulated high altitude on exercise at sea level
Authors: Januon E. , Terrados N. , Norman B. , Kaijser L.
Published: July 2010

Nine healthy men trained one leg under normobaric (N) conditions (N‐leg), the other leg under hypobaric (H; 572 mmHg) conditions (H‐leg) each one 30 min, 3–4 times per week for 4 weeks at 65% of the one‐legged maximal work load that could be performed for 2 min (Wmax). They performed one‐legged exercise tests to fatigue before and after the training period under N conditions at a load corresponding to 80% of one‐legged Wmax. Muscle biopsies were taken before training from one leg and after training both from the N‐leg and the H‐leg at rest and after 15‐min exercise and analysed for high‐energy phosphates and glycogen and their degradation products. Training under N as well as under H conditions improved local energy balance in the leg (less lactate and inosine monophosphate accumulation). However, a discrepancy was found between the previously demonstrated greater increase in local oxidative potential in the H‐leg than in the N‐leg and the local energy balance during submaximal exercise, which improved less in the H‐leg than in the N‐leg (lower energy charge and higher adenosine monophosphate content). Despite less improved local energy balance after 15 min of exercise, the time to fatigue was somewhat longer in the H‐leg.
Strength training and neuromuscular function in elderly people with total knee endoprosthesis
Authors: Perhonen M. , Komi P. V. , Häkkinen K. , von Bonsdorff H. , Partio H.
Published: July 2010

The effects of 1 year of intensive strength training on neuromuscular function were studied in elderly people operated for total endoprosthesis (n=30) divided into 3 groups: training pup 1 (TG1, n=11), training pup 2 (TG2, n=10) and control group (CG, n=9). After the operation, TG1 and TG2 trained every second day and the training was controlled by training diaries, and CG performed only conventional exercises by themselves. The overall volume of training in TG2 was 30% greater than in TG1. Neuromuscular function was examined by measuring maximal electromyography (EMG) and maximum voluntary isometric and dynamic strength of the knee extensor and flexor muscles. The range of motion of the knee joint and the cross‐sectional area (CSA) of the knee extensor muscles were also measured. After the preoperative tests, the same measurements were repeated 3, 6, 12, 24 and 52 weeks postoperatively. After the dramatic decreases in maximal isometric torque and EMG‐activity during the first postoperative weeks in all groups, TG2 showed the most remarkable improvement in neuromuscular function. For instance, the maximum isometric extension torque measured at 90° knee angle increased between the 24th and 52nd weeks. The increase in the EMG‐activity of the rectus femoris muscle was Significant between the 12th and 24th weeks. The CEA of the knee extensor muscles in TG2 was greater 1 year after the operation compared with the preoperative value. The intra‐ and extra‐articular swelling of the knee joint may have irritated the free nerve endings, leading to reflex inhibition with a concomitant decrease in EMG and strength of the knee extensor muscles. Because TG2 demonstrated the most remarkable improvement in neuromuscular function after the first postoperative weeks, intensive training programs can be successfully used in rehabilitation after a major knee operation, even in elderly people.
Changes in muscle stiffness caused by reduced joint mobility
Authors: Leivseth G. , Tindall A. , Løvaas E. , Relkeraas O.
Published: July 2010

The viscoelastic properties of gastrocnemius and soleus muscles were investigated at 3 different muscles lengths after 2 weeks with reduced mobility of the hindfoot Comparison was made with the same muscles from the contralateral leg. The peak‐to‐peak tension and dynamic elastic stiffness during passive stretching was greater in the muscles of the affected leg than in the controls. The peak‐to‐peak tension and the dynamic elastic stiffness of muscles subjected to simultaneous stretching and tetanic stimulation were equal to or greater in the affected muscles than in the controls. The active tension in the affected muscles subjected to stretching and tetanic stimulation was lower than in the control muscles. The collagen content in the affected muscles was greater than in the control muscles. It is likely that this is connected with the changes in the physical characteristics of the muscles.
Measurement of take‐off forces in ski jumping
Authors: Virmavirta M. , Koml P. V.
Published: July 2010

The force measuring system constructed under the frost rail inrun track element was used for measurement of take‐off forces in ski jumping. Several calibrations of the normal forces made on several days showed no significant differences between the calibration sessions. Loading the different places of the track element showed differences less than 5% between the places for the total 10‐m distance and less than 3% for the straight take‐off table. Two international‐level ski jumpers served as subjects during the testing of the system. Further preliminary results from 2 different performances techniques are presented. The force curves of subjects displayed totally different patterns: Two distinct peaks for subject MN (Fmax 25.46 ± 0.80 NkgBW−1) and only one peak for subject JH (Fmax 27.97 ± 0.98 N kgBW−1). A slight correlation was found between the Fmax and the length of the jump for one subject
Joint moments of force and quadriceps muscle activity during squatting exercise
Authors: Wretenberg P. , Feng Y. , Lindberg F. , Arboreilus U. p.
Published: July 2010

The relationship between hip and knee joint load and quadriceps muscle activity during squatting exercise to different depths was studied. Eight young national class Olympic weightlifters performed squatting exercise to 4 different knee flexion angles; 45°, 90°, parallel and deep squats. They held a barbell across their shoulders with a weight of 65% of their one‐repetition maximum. The loading moments of force about the hip and knee joints were calculated using a semidynamic method. Video was used for motion recording and electromyograhy for recording activity from die vastus lateralis, rectus femoris and biceps femoris muscles. The loading moment on the hip joint increased significantly from the 90° squat to the parallel, but there was no difference between the parallel and the deep. For the knee joint, there was no difference between the 45°, 90° and parallel, but for the deep squat the loading moment increased significantly. The muscular activity generally increased with increasing squatting depth, but mere were only minor insignificant differences between the parallel and the deep squats. We conclude that knee joint load can be limited by doing parallel instead of deep squats and that this will not decrease quadriceps muscle activity. To limit hip moment, the squat should not be deeper than 90°.
Criterion validity of a two‐kilometer walking test for predicting the maximal oxygen uptake of moderately to highly active middle‐aged adults
Authors: Laukkanen R. M. T. , Oja R. , Pasanen M. E. , Vuori I. M.
Published: July 2010

This work examined whether prediction models based on a 2‐km walking test are valid for predicting the Vo2max of middle‐aged, healthy, moderately to highly physically active adults. Sixty‐seven 35‐ to 45‐year‐old moderately active men and women and 44 35‐ to 55‐year‐old healthy men who participated regularly in marathon‐long sports competitions were studied. Vo2max was determined in an uphill walk‐run on a treadmill. The 2‐km walking test was conducted on a flat outdoor course. The subjects walked the distance as fast as they could. Walking time, heart rate at the end of the walk, age and body mass index were entered in the prediction formulas as established in the original study. The total errors of prediction and the correlation coefficients between the measured and predicted Vo2max (ml‐kg−1 min−1) for the moderately active women and men and for the competitors were 5.2, 5.7 and 7.7 ml kg−1 min−1 and 0.55, 0.79 and 0.60, respectively. The measured relative Vo2max was slightly underpredicted in all groups. The results suggest that the 2‐km walk test is a reasonably valid test of maximal aerobic power for moderately fit men and women, but less valid for very fit individuals.
Assessment of physical activity, fitness and performance in 76‐year‐olds
Authors: Frändin K. , Grimby G.
Published: July 2010

In a population study comprising 588 76‐year‐olds, the level of physical activity and physical performance, as well as associations between the variables included, was investigated. Men were significantly more active than women unless household activities were included in the physical activity scale, in which case no difference was found between men and women in the summer, whereas women were significantly more active than men in winter. In all performance variables (isometric knee extensor strength, stair‐climbing and maximal walking speed) men had significantly higher values than women. Correlations between physical activity and physical performance were moderate, but still indicate that the scale is a valid one for assessing physical activity.
Self‐reported asthma and exercise‐induced asthma symptoms in high‐level competitive cross‐country skiers
Authors: Heir T. , Oseid S.
Published: July 2010

The prevalence of asthma and exercise‐induced respiratory symptoms in 153 high‐level Norwegian cross‐country skiers and 306 control subjects were assessed in a postal survey. The response rates were 100% for the skiers and 79% for the controls. A present or past history of asthma was reported by 14% of the skiers and 5% of the controls. The prevalence of asthma increased signhcantly with increasing age among the skiers but not among the control subjects. The majority of the controls who reported asthma dated the onset of the disease to childhood, while the skiers dated the onset of asthma primarily to late adolescence or early adult life. The skiers used anti‐asthmatic medication significantly more often than did the controls. Exercise‐induced respiratory symptoms such as chest tightness, shortness of breath, cough, wheezing and sputum production were re‐ ported by 2–3 times as many skiers as controls. Exacerbation of respiratory symptoms was frequently associated with cold weather, humid weather or with recovering from an airway infection. The results of the present study indicate that cross‐country skiers may be at an increased risk for acquiring obstructive respiratory disorders.
Prevention of muscle soreness by pretreatment with antioxidants
Authors: Krotkiewski M. , Brzezinska Z. , Liu B. , Grimby G. , Palm S.
Published: July 2010

A free radical‐scavenging preparation (pollen extract) or the corresponding placebo was given to 50 volunteers over a period of 4 weeks to test the hypothesis that muscle soreness is associated with the generation of free radicals. The increase in malonyldialdehyde and lactate immediately after exercise both in blood and in muscle tissue was significantly lower after treatment with the scavenging preparation. The same was true for the prolonged post‐exercise increase in creatine kinase over a 5‐day period. The post‐exercise glycogen content of muscle was higher in the pollen extract group, as were the subjective feelings of pain, oedema, discomfort and tension in the working muscle. We conclude that the beneficial preventive effect of pollen extract on post‐exercise muscle soreness and lowering of the concentration of lipid peroxides indicate that free radicals are probably involved in the development of muscle soreness.
Aging of human muscle: structure, function and adaptability
Authors: Porter M. M. , Vandervoort A. A. , Lexell J.
Published: July 2010

With increasing age, human skeletal muscles gradually decrease in volume, mainly due to a reduced number of motor units and muscle fibers, and a reduced size of type 2 fibers. As a result, progressive weakening and impaired mobility occur. High‐resistance strength training is beneficial, even in the very old, and could possibly reverse some of the detrimental effects of age‐related weakness. The importance of exercise for older people affords an excellent opportunity for the medicine community as a major source of information and promotion of physical activity for this rapidly growing segment of the population. In this review, we summarize the current knowledge of the effects of aging on the human neuromuscular system, describe some of the major underlying mechanisms of the aging atrophy and focus on the importance of strength training to improve muscle function in older people.
Overuse injuries of the lower extremity in runners
Authors: Rolf C.
Published: July 2010

The purpose of this article is to review the literature on overuse injuries of the lower extremity in runners and to discuss briefly today's knowledge concerning etiology, diagnosis and treatment. Running is a natural entity in many sports and a majority of runners will sustain one or more overuse injuries throughout the career, in most cases affecting the lower extremity. A runner may be regarded as an athlete who regularly runs as the predominant physical acitivty. From that point, we should subdivide the definition “runner” considering the character of different sports or recreational activities performed. Overuse injuries are often described merely from symptoms, including several different etiological and pathoan‐atomic correlates covering a variety of ailments. The clinical approach should be focused on a thorough history and physical examination. Analysis of possible injury mechanisms, correction of associated extrinsic and intrinsic factors and advice on alternative training should be given. A knowledge of specific demands from the type of running performed is necessary to evaluate the symptoms presented. Overuse etiology has to be considered multifactorial with a yet unsolved exact pathophysiology needing further research. The definition of a “runner”, of “running” and of “overuse injury” should be established and agreed upon. This review attempts to draw attention to the huge multidisciplinary work that has to be done to better understand the mechanisms causing an overuse injury in a runner and to define diagnoses on a scientific base, whether or not excentric or intrinsic factors predispose or trigger.
Heavy‐resistance training in older Scandinavian men and women: short‐ and long‐term effects on arm and leg muscles
Authors: Lexell J. , Downham D. Y. , Larsson Y. , Bruhn E. , Morsing B.
Published: July 2010

The short‐ and long‐term effects of heavy‐resistance training (85% of one‐repetition maximum (RM)) on elbow flexion and knee extension dynamic and isokinetic strength and on morphology in the biceps brachii and vastus lateralis muscles were evaluated during 1 year in 35 Scandinavian men and women, aged 70–77 years, 12 of whom formed a control group. After the first 11 weeks of training (n=23; 3 times/week) elbow flexion and knee extension dynamic strength (1 RM) had increased [mean±SD] 49%±16 and 163%±75, respectively, with no significant difference between men and women. For the following 27 weeks, strength was maintained with one training session per week (n=12) but dropped without training (n=11). After the final 11 weeks of training (n=11; 3 times/week), strength had further increased 32%±16 in both the arm and the leg. Isokinetic strength measurements (Cybex II; 30%s) revealed similar but smaller gains than for dynamic strength. Muscle biopsies (n=20) taken at the start and after the first 11 weeks of training showed a significant increase in the area of both type 1 and type 2 fibers in the biceps brachii muscle and a positive significant correlation between the percentage increase in the proportional area of type 2 fibers in the vastus lateralis muscle and the percentage increase in knee extension dynamic muscle strength. In conclusion, older Scandinavian men and women have a high capacity both to improve and to maintain muscle strength, some of which is mediated through an adaptation in the muscle fiber type population.
Patterns of intense physical activity among 15‐ to 30‐year‐old Finns
Authors: Raitakari O. T. , Taimela S. , Porkka K. V. K. , Leino M. , Telama R. , Dahl M. , Viikari J. S. A.
Published: July 2010

Previous studies have reported increasing trends in physical activity in the Finnish population. These reports have not, however, included the perspective of cardiorespiratory stress in adolecent and young adults. We examined the present patterns of physical activity among Finnish adolescents and young adults in 1992. We specifically assessed whether the young people experience the volume of physical activity that is believed to stress the cardiorespiratory system appropriately in order to increase the level of fitness. The subjects in the present study were participants of a large multicenter study of atherosclerosis precursors in children and young adults. Physical activity was measured with a self‐administered questionnaire in 2255 adolescents and young adults (1015 males and 1240 females). The proportion of subjects undertaking the volume of physical activity believed to benefit the cardiorespiratory system appropriately was 19%. The proportion was higher in males than in females (26 vs. 13%). The proportion of active subjects became smaller in older age groups in both sexes. Half the study population (51% of the males; 48%) of the females) reported frequent leisure‐time physical activity less than once a month. In conclusion, Finnish adolescents and young adults have low levels of physical activity on the average, and many young Finns seldom undertake the volume of physical activity believed to benefit the cardiopulmonary system. Young males seem to be physically more active than females.
Functional restoration in chronic low back pain
Authors: Bendix T. , Bendix A. F. , Busch E. , Jordan A. , Bendix Tom
Published: July 2010

Conventional treatments have not slowed down the ever expanding low back pain (LBP) problem. Traditional treatment has most probably contributed to the growth of the problem. Therefore, in a search for new solutions, ‘functional restoration’ has been devised. In connection with chronic LBP the term has been associated with a full‐day program lasting from 3 to 5 weeks. it includes multidisciplinary treatment of patients in groups with intensive physical and ergonomic training, psychological pain management, back school, as well as teaching in social/work related issues. The key concepts are ‘acceptance of the pain’, ‘activity’, ‘self‐responsibility’, ‘multidisciplinary’ and ‘quantitative functional evaluation (QFE)’. The latter is aimed so that the participants can feel the physical improvement, encouraging them to be able to go back to work, or at least to lead a more active life style. Several controlled studies suggest a lasting effect in terms of regaining their ability to work and improving pain behavior for a good part of disabled chronic LBP patients. However, it is noteworthy that randomized studies seemingly show poorer results than studies not employing randomized controls.
Age, body composition, aerobic fitness and health condition as risk factors for musculoskeletal injuries in conscripts
Authors: Heir T. , Eide G.
Published: July 2010

Musculoskeletal injuries occur frequently in connection with physical activity. More information was sought on pretraining factors that may predispose to such injuries. Data were obtained on the age, height, weight, aerobic fitness as measured by a 3000‐m run test, and health as assessed on the basis of a medical examination, of 912 male conscripts prior to an 8‐week period of basic military and physical training. Injuries were registered as they occurred by doctors attached to the training camp. Every fourth to fifth conscript suffered one or more musculo‐skeletal injuries during basic training. Achilles tendinitis, low back pain, periostitis or compartment syndromes, and overuse knee injuries were the most frequent diagnosis groups. In 74% of the injuries, a tentative cause was related to organized service activities. According to univariate analyses, risk factors were age over 23 years, high body mass index (BMI), slow run times and dysfunctions of the back or lower limbs. A lower classification of mental health, but not dysfunctions of the lower limbs, was an additional risk factor if only injuries with causes connected with organized service activities were considered. Height and weight were not associated with injuries. In multiple logistic regression analysis, age and 3000‐m run times were masked by correction for BMI, while BMI, dysfunctions of the back and lower limbs, and reduced mental health showed the same significance as in the univariate analyses.
Quadriceps muscle performance in sitting and standing in young women with patellofemoral pain syndrome and young healthy women
Authors: Thomeé R. , Grimby G. , Svantesson U. , Österberg U.
Published: July 2010

The aim of this study was to evaluate and compare muscular activation in sitting and standing in patients with patellofemoral pain syndrome and healthy controls. Eleven women with patellofemoral pain syndrome and nine healthy controls were evaluated regarding: (a) muscle performance in sitting compared to standing ‐ knee extensor torque was registered in sitting with a Kin Com dynamometer and in standing with a force plate, and quadriceps muscle activity was registered with EMG in both sitting and standing; and (b) ability to maximally voluntarily activate during sitting isometric knee extension.

Maximally tolerated single‐twitch electrical stimulation was superimposed on 20, 40, 60, 80 and 100% of maximal voluntary activation. Additional torque from the single twitch was documented. Five patients and all nine controls were tested twice (tests a and b) with 2 days between tests, and high reproducibility could be demonstrated. A significantly higher torque during sitting compared with standing was found in both patients and controls, but with a significant correlation between sitting and standing torque values. No significant difference was found between patients and controls. Single‐twitch electrical stimulation superimposed on maximal voluntary activation resulted in increased torque in two of the nine controls compared to 10 of the 11 patients. The average increased torque in the patients were significantly higher than in the controls and estimated to 18%. It was concluded that sitting isometric measurements are representative of the ability to produce standing isometric knee torque. A moderate degree of inhibition was demonstrated during sitting strength measurements in the patients (not studied in standing).
A treadmill test of sprint running
Authors: Falk B. , Weinstein Y. , Dotan R. , Abramson D. A. , Mann‐Segal D. , Hoffman J. R.
Published: July 2010

Anaerobic power is characterized by a high degree of specificity regarding both the recruited muscles as well as the recruitment pattern. The popular Wingate Anaerobic Test (WAnT) is a cycling test that does not satisfy the need for a running‐specific anaerobic test. We describe such a test, using a novel type of a commercially available treadmill (BRL 1800, Gymrol, France). The ergometer is equipped with a torque motor to neutralize the frictional resistance of the treadmill belt, and a hip‐belt harness connected to a horizontal rod. Force applied to the harness is monitored by a strain gauge mounted on the rod, while vertical movement is monitored by a potentiometer at the posterior fixed end of the rod. These, in conjunction with the treadmill belt speed, enable the computation of horizontal and vertical power as well as the combined total output. Power is calculated both as ‘peak’ power (highest 2.5 s segment) and ‘mean’ power (20 s duration). Preliminary results of young athletes were generally consistent with the expected age‐related changes in anaerobic power. Values obtained on the anaerobic treadmill were always higher than the corresponding WAnT values previously obtained in comparable age groups. The higher values were probably due to the larger muscle mass involved and the shorter peak and mean power durations (2.5 and 20 s versus 5 and 30 s in the WAnT, respectively). This test should enable not only running‐specific anaerobic power monitoring but also the characterization of the relationship between the horizontal and vertical components of that power.
Popliteus function in ACL‐deficient patients
Authors: Weresh M. J. , Gabel R. H. , Brand R. A. , Tearse D. S.
Published: July 2010

Anterior cruciate ligament (ACL) injuries commonly result in anterolateral rotary instability and a ‘pivot shift’ phenomenon. Since popliteus muscle stimulation causes a pivot shift, some postulate the popliteus muscle plays a role in causing pivot shifts. To see if patients with pivot shifts exhibited excessive popliteus muscle activity, we studied fine‐wire EMGs of the popliteus in 16 normal subjects and 10 ACL‐deficient subjects. Subjects performed six activities (level walking and jogging, ascending walking and jogging, and descending walking and jogging). Except for minor timing differences in ascending treadmill and ascending jogging, the signals were similar for injured and uninjured limbs; similar variance ratios suggested similar pattern variability. Thus, we observed only minor popliteus EMG signal differences in this group of patients. We conclude that the popliteus muscle does not actively contribute to instability in the studied activities.
The treatment of acute soft tissue trauma in Danish emergency rooms
Authors: Johannsen F. , Langberg H.
Published: July 2010

Rest, ice, compression, elevation (RICE) is the most recommended treatment for acute traumatic soft tissue injuries. A questionnaire was given to all Danish emergency rooms (n= 51) regarding their routines for acute treatment of ankle sprains and muscle contusions. Complete answers were received from 37 emergency rooms (73%), covering the treatment of 111 ankle sprains and 101 muscle contusions. Treatment with RICE was given in a minority of injuries, ice (21%), compression (32%) and elevation (58%) similarly between injury types. A complete RICE treatment was rarely applied (3%). Verbal information on RICE and rehabilitation was given in less than half of the cases. We conclude that the acute treatment of ankle sprains and muscle contusions in the Danish emergency rooms is not applied in accordance with consensus from international literature, and that the instruction in rehabilitation should be improved.
Effect of intensive training on lower leg structural strength: an in vivo study in ovariectomized rats
Authors: Kaastad T. S. , Reikerås O. , Narum S. , Madsen J. E. , Haug E. , Obrant K. J. , Nordsletten L.
Published: July 2010

The aim of this study was to investigate the effect of training on the in vivo tibial structural strength during the development of post‐ovariectomy osteoporosis. Seventeen mature Wistar rats (215 g) were ovariectomized and randomized into two groups. The sedentary control group was kept cage confined, while 3 days postoperatively the trained group started treadmill running with high intensity for 1 h 5 days a week. All were given a low calcium diet (Ca 0.01%). After 8 weeks the animals were anaesthetized and the right lower legs fractured during muscle contraction in three‐point ventral bending. The left legs were fractured at the same level after removal of all soft tissues. Histomorphometry of the meta‐ and diaphysis of the distal tibiae was performed. Weight‐gain was higher in sedentary (108 g) than in trained (61 g) rats (P < 0.0001). There were no significant differences in mechanical results between the groups at in vivo or in vitro fracture. Correcting for weight‐gain differences did not change these results. Histomorphometry showed no differences between the groups. Corticosterone was higher in trained than in sedentary rats (P < 0.02), and corticosterone may have had a negative influence both on muscle and bone. The study could not show an effect of high intensity training in the early phase after ovariectomy on in vivo or in vitro fracture strength.
Skeletal effects of menstrual disturbances in athletes
Authors: Bennell K. L. , Malcolm S. A. , Wark J. D. , Brukner P. D.
Published: July 2010

This article reviews the skeletal effects and clinical implications of menstrual disturbances in active women. At the lumbar spine, menstrual disturbances are associated with premature bone loss or failure to reach peak bone mass, while appendicular sites are less affected. This suggests that trabecular bone is more sensitive to hormonal stimuli and less responsive to mechanical loading than cortical bone. Although the mechanisms responsible for the detrimental effects of menstrual disturbances are likely to be multifactorial, low circulating levels of oestrogen are thought to be the main cause. The clinical significance of menstrual disturbances depends upon a number of factors, including type of sport, genetic back‐ground, body composition and calcium intake. Not all athletes who present with menstrual disturbances will develop osteopenia. Nevertheless, the risk of stress fracture does seem to be increased in athletes with menstrual disturbances and with lower bone density. Whether athletes with menstrual disturbances are at a greater risk for osteoporosis in later life is not yet known. Bone loss can be at least partially reversed, especially with the spontaneous resumption of menses. This may serve to offset any previous increased risk of osteoporsis. Furthermore, other factors, apart from low bone mass, act to determine the likelihood of osteoporotic fractures. Therefore, the clinical significance of menstrual disturbances associated with exercise participation needs to be established for each individual athlete. Bone densitometry may guide the clinician in this respect and assist in the formulation of appropriat management strategies.
Passive knee extension test to measure hamstring muscle tightness
Authors: Fredriksen H. , Dagfinrud H. , Jacobsen V. , Mæhlum S.
Published: July 2010

The purpose of this study was twofold: (a) to examine the reliability of a test designed to measure tightness of the hamstring muscles, and (b) to assess the pelvic motion during this test. The knee was passively extended by a standardized force, while the hip was stabilized in 120 degrees of flexion. The knee angle was measured with a goniometer and represents the hamstring tightness. Twenty‐eight test‐retests were performed. The correlation coefficient was found to be 0.99, and the CV was found to be 1%. We used a MacReflex measurement system to assess the associated pelvic motion. Eight measurements were taken, and the median of associated pelvic motion was 4.1 degrees. It is concluded that the passive knee extension test is a simple and reliable method, and the associated pelvic motion is minimal.
Aerobic workout and bone mass in females
Authors: Alfredson H. , Nordström P. , Lorentzon R.
Published: July 2010

This cross‐sectional study aimed to investigate bone mass in females participating in aerobic workout. Twenty‐three females (age 24.1±2.7 years), participating in aerobic workout for about 3 hours/week, were compared with 23 age‐, weight‐ and height‐matched non‐active females. Areal bone mineral density (BMD) was measured in total body, head, whole dominant humerus, lumbar spine, right femoral neck, Ward's triangle, trochanter femoris, in specific sites in right femur diaphysis, distal femur, proximal tibia and tibial diaphysis, and bone mineral content (BMC) was measured in the whole dominant arm and right leg, using dual energy X‐ray absorptiometry. The aerobic workout group had significantly (P<0.05–0.01) higher BMD in total body (3.7%), lumbar spine (7.8%), femoral neck (11.6%), Ward's triangle (11.7%), trochanter femoris (9.6%), proximal tibia (6.8%) and tibia diaphysis (5.9%) compared to the non‐active controls. There were no differences between the groups concerning BMD of the whole dominant humerus, femoral diaphysis, distal femur and BMC and lean mass of the whole dominant arm and right leg. Leaness of the whole dominant arm and leg was correlated to BMC of the whole dominant arm and right leg in both groups. In young females, aerobic workout containing alternating high and low impact movements for the lower body is associated with a higher bone mass in clinically important sites like the lumbar spine and hip, but muscle strengthening exercises like push‐ups and soft‐glove boxing are not associated with a higher bone mass in the dominant humerus. It appears that there is a skeletal adaptation to the loads of the activity.
Spinal epidural lipomatosis. Case report and review of the literature
Authors: Fiirgaard B. , Madsen F. H.
Published: July 2010

Spinal epidural lipomatosis (SEL) is a condition in which excess adipose tissue is deposited circumferentially about the spinal cord in the epidural space. It is most frequently seen in patients on chronic glucocorticosteroid therapy for a variety of medical problems. This is a case report of lumbar epidural lipomatosis in a bodybuilder with radiculopathy supposedly induced by anabolic steroid intake.
Cutaneous blood flow rate in areas with and without arterovenous anastomoses during exercise
Authors: Midttun M. , Sejrsen P.
Published: July 2010

In 10 healthy subjects, skin blood flow rate was measured in the thumb pulp by the heat‐washout method, and in the skin fold between the thum and the forefinger by the 133Xe‐washout method. The former but not the latter skin area contains arterovenous anastomoses (AVAs). In response to 10 min moderate cycle exercise, an instantaneous decrease in flow was seen in the thumb pulp followed after about 4.6 min by an increase to resting levels. Blood flow in the skin fold remained constant. The results indicate that the initial reduction in blood flow rate and later increase observed in the finger at the onset of moderate exercise take place in the AVAs and not in the capillaries.
The effect of bracing on extension strength in patients with ACL insufficneicy
Authors: Warming T. , Jørgensen U.
Published: July 2010

One of the problems following an anterior cruciate ligament (ACL) injury is to regain strength. We tested 11 patients (5 men, 6 women), mean age 28.4 years, with unilateral ACL insufficiency, with two braces (Donjoy Legend, and Bledsoe Brace Force III) versus a placebo brace. The patients were tested on a Biodex Dynamometer at 60 and 180 deg/s in an isokinetic mode. The experiment was designed as a comparative study in a crossover design with the stable knee as the patient's own control. We found no statistically significant effect of the two braces compared to a placebo brace under the test conditions, and no correlation between knee laxity and the effect of bracing.