Description

The focus of the European Journal of Applied Physiology is on human integrative physiology. Accordingly the journal publishes original research utilising a wide range of techniques and approaches which can contribute to our understanding of the function of the intact healthy human body under a variety of environmental and exercise conditions. Such conditions may include those experienced in occupational sporting recreational and daily activities thoughout the human life-span from childhood to old age. Techniques and approaches utilised in recent published papers include: molecular and developmental biology biomechanics biochemistry endocrinology and nutrition as well as all aspects of human physiology. "Theoretical papers as well as those of a clinical nature and those dealing with animal work are not excluded from consideration but must be clearly relevant to human physiology."

Publisher details

Springer Verlag

Publications in this journal

• Effects of high-intensity and blood flow-restricted low-intensity resistance training on carotid arterial compliance: role of blood pressure during training sessions.

  Authors: Hayao Ozaki, Tomohiro Yasuda, Riki Ogasawara, Mikako Sakamaki-Sunaga, Hisashi Naito, Takashi Abe

  European journal of applied physiology.

  We examined the effects of high-intensity resistance training (HIT) and low-intensity blood flow-restricted (LI-BFR) resistance training on carotid arterial compliance. Nineteen young men wereWe examined the effects of high-intensity resistance training (HIT) and low-intensity blood flow-restricted (LI-BFR) resistance training on carotid arterial compliance. Nineteen young men were randomly divided into HIT (n = 9) or LI-BFR (n = 10) groups. The HIT and LI-BFR groups performed 75 and 30 %, respectively, of one-repetition maximum (1-RM) bench press exercise, 3 days per week for 6 weeks. During the training sessions, the LI-BFR group wore elastic cuffs around the most proximal region of both arms. Muscle cross-sectional area (CSA), 1-RM strength, and carotid arterial compliance were measured before and 3 days after the final training session. Acute changes in systolic arterial pressure (SAP), plasma endothelin-1 (ET-1), nitrite/nitrate (NOx), and noradrenalin concentrations were also measured during and after a bout of training session. The training led to significant increases (P < 0.01) in bench press 1-RM and arm and chest muscle CSA in the two training groups. Carotid arterial compliance decreased significantly (P < 0.05) in the HIT group, but not in the LI-BFR group. There was a significant correlation (r = -0.533, P < 0.05) between the change in carotid arterial compliance and the acute change in SAP during training sessions; however, ET-1 and NOx did not correlate with carotid arterial compliance. Our results suggest that muscle CSA and strength increased following 6 weeks of both HIT and LI-BFR training. However, carotid arterial compliance decreased in only the HIT group, and the changes were correlated with SAP elevations during exercise sessions.

• Free-running circadian rhythms of muscle strength, reaction time, and body temperature in totally blind people.

  Authors: Camila Fabiana Rossi Squarcini, Maria Laura Nogueira Pires, Cleide Lopes, Ana Amélia Benedito-Silva, Andrea Maculano Esteves, Germaine Cornelissen-Guillaume, Carolina Matarazzo, Danilo Garcia, Maria Stella Peccin da Silva, Sergio Tufik, Marco Túlio de Mello

  European journal of applied physiology.

  Light is the major synchronizer of circadian rhythms. In the absence of light, as for totally blind people, some variables, such as body temperature, have an endogenous period that is longer than 24Light is the major synchronizer of circadian rhythms. In the absence of light, as for totally blind people, some variables, such as body temperature, have an endogenous period that is longer than 24 h and tend to be free running. However, the circadian rhythm of muscle strength and reaction time in totally blind people has not been defined in the literature. The objective of this study was to determine the period of the endogenous circadian rhythm of the isometric and isokinetic contraction strength and simple reaction time of totally blind people. The study included six totally blind people with free-running circadian rhythms and four sighted people (control group). Although the control group required only a single session to determine the circadian rhythm, the blind people required three sessions to determine the endogenous period. In each session, isometric strength, isokinetic strength, reaction time, and body temperature were collected six different times a day with an interval of at least 8 h. The control group had better performance for strength and reaction time in the afternoon. For the blind, this performance became delayed throughout the day. Therefore, we conclude that the circadian rhythms of strength and simple reaction time of totally blind people are within their free-running periods. For some professionals, like the blind paralympic athletes, activities that require large physiological capacities in which the maximum stimulus should match the ideal time of competition may result in the blind athletes falling short of their expected performance under this free-running condition.

• Erratum to: Effects of eccentric exercise on systemic concentrations of pro- and anti-inflammatory cytokines and prostaglandin (E2): comparison between young and postmenopausal women.

  Authors: Miguel Soares Conceição, Cleiton Augusto Libardi, Felipe Romano Damas Nogueira, Valéria Bonganha, Arthur Fernandes Gáspari, Mara Patrícia Traina Chacon-Mikahil, Cláudia Regina Cavaglieri, Vera Aparecida Madruga

  European journal of applied physiology.

• Partial heat acclimation of athletes with spinal cord lesion.

  Authors: Paul C Castle, B Pasan Kularatne, John Brewer, Alexis R Mauger, Ross A Austen, James A Tuttle, Nick Sculthorpe, Richard W Mackenzie, Neil S Maxwell, Anthony D J Webborn

  European journal of applied physiology.

  Heat acclimation (HA) can improve thermoregulatory stability in able-bodied athletes in part by an enhanced sweat response. Athletes with spinal cord lesion are unable to sweat below the lesion andHeat acclimation (HA) can improve thermoregulatory stability in able-bodied athletes in part by an enhanced sweat response. Athletes with spinal cord lesion are unable to sweat below the lesion and it is unknown if they can HA. Five paralympic shooting athletes with spinal cord lesion completed seven consecutive days HA in hot conditions (33.4 ± 0.6 °C, 64.8 ± 3.7 %rh). Each HA session consisted of 20 min arm crank exercise at 50 % [Formula: see text] followed by 40 min rest, or simulated shooting. Aural temperature (T (aur)) was recorded throughout. Body mass was assessed before and after each session and a sweat collection swab was fixed to T12 of the spine. Fingertip whole blood was sampled at rest on days 1 and 7 for estimation of the change in plasma volume. Resting T (aur) declined from 36.3 ± 0.2 °C on day 1 to 36.0 ± 0.2 °C by day 6 (P < 0.05). During the HA sessions mean, T (aur) declined from 37.2 ± 0.2 °C on day 1, to 36.7 ± 0.3 °C on day 7 (P < 0.05). Plasma volume increased from day 1 by 1.5 ± 0.6 % on day 7 (P < 0.05). No sweat secretion was detected or changes in body mass observed from any participant. Repeated hyperthermia combined with limited evaporative heat loss was sufficient to increase plasma volume, probably by alterations in fluid regulatory hormones. In conclusion, we found that although no sweat response was observed, athletes with spinal cord lesion could partially HA.

• Overload training inhibits phagocytosis and ROS generation of peritoneal macrophages: role of IGF-1 and MGF.

  Authors: Weihua Xiao, Peijie Chen, Ru Wang, Jingmei Dong

  European journal of applied physiology.

  We tested the hypothesis that overload training inhibits the phagocytosis and the reactive oxygen species (ROS) generation of peritoneal macrophages (Mϕs), and that insulin-like growthWe tested the hypothesis that overload training inhibits the phagocytosis and the reactive oxygen species (ROS) generation of peritoneal macrophages (Mϕs), and that insulin-like growth factor-1(IGF-1) and mechano-growth factor (MGF) produced by macrophages may contribute to this process. Rats were randomized to two groups, sedentary control group (n = 10) and overload training group (n = 10). The rats of overload training group were subjected to 11 weeks of experimental training protocol. Blood sample was used to determine the content of hemoglobin, testosterone, and corticosterone. The phagocytosis and the ROS generation of Mϕs were measured by the uptake of neutral red and the flow cytometry, respectively. IGF-1 and MGF mRNA levels in Mϕs were determined by real-time PCR. In addition, we evaluated the effects of IGF-1 and MGF peptide on phagocytosis and ROS generation of Mϕs in vitro. The data showed that overload training significantly decreased the body weight (19.3 %, P < 0.01), the hemoglobin (13.5 %, P < 0.01), the testosterone (55.3 %, P < 0.01) and the corticosterone (40.6 %, P < 0.01) in blood. Moreover, overload training significantly decreased the phagocytosis (27 %, P < 0.05) and the ROS generation (35 %, P < 0.01) of Mϕs. IGF-1 and MGF mRNA levels in Mϕs from overload training group increased significantly compared with the control group (21-fold and 92-fold, respectively; P < 0.01). In vitro experiments showed that IGF-1 had no significant effect on the phagocytosis and the ROS generation of Mϕs. Unlike IGF-1, MGF peptide impaired the phagocytosis of Mϕs in dose-independent manner. In addition, MGF peptide of some concentrations (i.e., 1, 10, 50, 100 ng/ml) significantly inhibited the ROS generation of Mϕs. These results suggest that overload training inhibits the phagocytosis and the ROS generation of peritoneal macrophages, and that MGF produced by macrophages may play a key role in this process. This may represent a novel mechanism of immune suppression induced by overload training.

• Effect of dehydroepiandrosterone administration on recovery from mix-type exercise training-induced muscle damage.

  Authors: Yi-Hung Liao, Kun-Fu Liao, Chung-Lan Kao, Chung-Yu Chen, Chih-Yang Huang, Wei-Hsiang Chang, John L Ivy, Jeffrey R Bernard, Shin-Da Lee, Chia-Hua Kuo

  European journal of applied physiology.

  This study aimed to determine the role of DHEA-S in coping against the exercise training mixing aerobic and resistance components. During 5-day successive exercise training, 16 young maleThis study aimed to determine the role of DHEA-S in coping against the exercise training mixing aerobic and resistance components. During 5-day successive exercise training, 16 young male participants (19.2 ± 1.2 years) received either a placebo (flour capsule) or DHEA (100 mg/day) in a double-blinded and placebo-controlled design. Oral DHEA supplementation significantly increased circulating DHEA-S by 2.5-fold, but a protracted drop (~35 %) was observed from Day 3 during training. In the Placebo group, only a minimal DHEA-S reduction (~17 %) was observed. Changes in testosterone followed a similar pattern as DHEA-S. Muscle soreness was elevated significantly on Day 2 for both groups to a similar extent. Lower muscle soreness was observed in the DHEA-supplemented group on Day 3 and Day 6. In the Placebo group, training increased circulating creatine kinase (CK) levels by approximately ninefold, while only a threefold increase was observed in the DHEA-supplemented group. This mix-type exercise training improved glucose tolerance in both groups, while lowering the insulin response to the glucose challenge, but no difference between treatments was observed. Our results suggest that DHEA-S may play a role in protecting skeletal muscle from exercise training-induced muscle damage.

• Time-course response in serum markers of bone turnover to a single-bout of electrical stimulation in patients with recent spinal cord injury.

  Authors: Alfredo Arija-Blázquez, Silvia Ceruelo-Abajo, María S Díaz-Merino, Juan Antonio Godino-Durán, Luís Martínez-Dhier, José Florensa-Vila

  European journal of applied physiology.

  The objective of the present repeat-measures study was to determine whether plasma serum levels of testosterone, cortisol, osteocalcin or type I collagen C-telopeptide (CT) are acutely affectedThe objective of the present repeat-measures study was to determine whether plasma serum levels of testosterone, cortisol, osteocalcin or type I collagen C-telopeptide (CT) are acutely affected following an electro-myostimulation (EMS) bout, and their relation to bone mineral density and muscle mass. Ten men with recent (8 weeks) thoracic spinal cord injury (SCI) (ASIA A) and 10 age-matched able-bodied (AB) men performed one EMS bout on the quadriceps femoris muscle. Blood samples were drawn at basal condition, immediately after EMS, and 15 min, 30 min, 24 h and 48 h post-EMS. Muscle cross-sectional area was measured by magnetic resonance imaging. Bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry. In the SCI group, a significant decrease in testosterone, cortisol and CT together with a significant increase in testosterone/cortisol ratio and osteocalcin/CT ratio was observed after EMS. For the AB subjects, only testosterone and CT decreased significantly following EMS. Muscle size was only related to testosterone/cortisol ratio in the SCI sample (R = 0.659, p < 0.05), whereas BMD did not show any relation to any biomarker. Acute EMS in recent spinal cord injured men seems to induce positive effects on bone turnover biomarkers, and anabolic and catabolic hormones.

• Eccentric exercise inhibits the H reflex in the middle part of the trapezius muscle.

  Authors: Steffen Vangsgaard, Lars T Nørgaard, Brian K Flaskager, Karen Søgaard, Janet L Taylor, Pascal Madeleine

  European journal of applied physiology.

  The objectives of this study were to (1) investigate the modulation of the H reflex immediately after and 24 h after eccentric exercise in the presence of delayed-onset muscle soreness (DOMS) and (2)The objectives of this study were to (1) investigate the modulation of the H reflex immediately after and 24 h after eccentric exercise in the presence of delayed-onset muscle soreness (DOMS) and (2) test the reproducibility of the H reflex in trapezius across days. H reflexes were recorded from the dominant middle trapezius muscle by electrical stimulation of the C3/4 cervical nerve in ten healthy subjects. DOMS was induced by eccentric exercise of the dominant shoulder. H reflexes were obtained in four sessions: "24 h before", "Pre", "Post", and "24 h after" eccentric exercise. Ratios of maximal H reflex and M wave responses (H (max)/M (max)) were compared between sessions. In addition, a between session comparison was done for the ratios of H reflex amplitudes (H (i_75)/M (max), and H (i_50)/M (max)) obtained from the stimulus intensity needed to obtain 75 and 50 % of H (max) at "24 h before". No ratio changes were found when comparing "24 h before" and "Pre" recordings. A decrease in H (i_50)/M (max) was found at "Post" (P < 0.05) and decreases in both H (i_75)/M (max) and H (i_50)/M (max) were observed at "24 h after" (P < 0.05). This study presented evidence that an acceptable day-to-day reproducibility of the H reflex could be obtained with the applied experimental setup. Furthermore, immediately after and 24 h after exercise a stronger stimulus intensity was needed to reach the same magnitude of the H reflex reflecting that the recruitment curve was shifted to the right. This modulation of the stimulus-response relationship could be caused by presynaptic inhibition of Ia afferent fibres' input to the motoneuron by group III and IV afferents.

• Changes in arterial blood pressure elicited by severe passive heating at rest is associated with hyperthermia-induced hyperventilation in humans.

  Authors: Naoto Fujii, Masashi Ichinose, Yasushi Honda, Bun Tsuji, Kazuhito Watanabe, Narihiko Kondo, Takeshi Nishiyasu

  European journal of applied physiology.

  The arterial blood pressure and ventilatory responses to severe passive heating at rest varies greatly among individuals. We tested the hypothesis that the increase in ventilation seen during severeThe arterial blood pressure and ventilatory responses to severe passive heating at rest varies greatly among individuals. We tested the hypothesis that the increase in ventilation seen during severe passive heating of resting humans is associated with a decrease in arterial blood pressure. Passive heating was performed on 18 healthy males using hot water immersion to the level of the iliac crest and a water-perfused suit. We then divided the subjects into two groups: MAP(NOTINC) (n = 8), whose mean arterial blood pressure (MAP) at the end of heating had increased by ≤3 mmHg, and MAP(INC) (n = 10), whose MAP increased by >3 mmHg. Increases in esophageal temperature (T (es)) elicited by the heating were similar in the two groups (+2.3 ± 0.3 vs. +2.4 ± 0.4 °C). Early during heating (increase in T (es) was <1.5 °C), MAP, minute ventilation ([Formula: see text]), and end-tidal CO(2) pressure ([Formula: see text]) were similar between the groups. However, during the latter part of heating (increase in T (es) was ≥1.5 °C), the increase in [Formula: see text] and decrease in [Formula: see text] were significantly greater or tended to be greater, while the increase in MAP was significantly smaller in MAP(NOTINC) than MAP(INC). Among all subjects, heating-induced changes in [Formula: see text] significantly and negatively correlated with heating-induced changes in MAP during the latter part of heating (r = -0.52 to -0.74, P < 0.05). These results suggest that, in resting humans, 25-50 % of the variation in the magnitude of the arterial blood pressure response to severe passive heating can be explained by the magnitude of hyperthermia-induced hyperventilation.

• Relative importance of different surface regions for thermal comfort in humans.

  Authors: Mayumi Nakamura, Tamae Yoda, Larry I Crawshaw, Momoko Kasuga, Yuki Uchida, Ken Tokizawa, Kei Nagashima, Kazuyuki Kanosue

  European journal of applied physiology.

  In a previous study, we investigated the contribution of the surface of the face, chest, abdomen, and thigh to thermal comfort by applying local temperature stimulation during whole-body exposure toIn a previous study, we investigated the contribution of the surface of the face, chest, abdomen, and thigh to thermal comfort by applying local temperature stimulation during whole-body exposure to mild heat or cold. In hot conditions, humans prefer a cool face, and in cold they prefer a warm abdomen. In this study, we extended investigation of regional differences in thermal comfort to the neck, hand, soles, abdomen (Experiment 1), the upper and lower back, upper arm, and abdomen (Experiment 2). The methodology was similar to that used in the previous study. To compare the results of each experiment, we utilized the abdomen as the reference area in these experiments. Thermal comfort feelings were not particularly strong for the limbs and extremities, in spite of the fact that changes in skin temperature induced by local temperature stimulation of the limbs and extremities were always larger than changes that were induced in the more proximal body parts. For the trunk areas, a significant difference in thermal comfort was not observed among the abdomen, and upper and lower back. An exception involved local cooling during whole-body mild cold exposure, wherein the most dominant preference was for a warmer temperature of the abdomen. As for the neck and abdomen, clear differences were observed during local cooling, while no significant difference was observed during local warming. We combined the results for the current and the previous study, and characterized regional differences in thermal comfort and thermal preference for the whole-body surface.

• Walking promotes metabolic and baroreflex sensitivity improvement in fructose-fed male rats.

  Authors: Jacqueline F Machi, Nathália Bernardes, Cristiano Mostarda, Ivana Cinthya Moraes-Silva, Maria Cláudia Irigoyen, Kátia De Angelis, Rogério B Wichi

  European journal of applied physiology.

  The aim of this study was to investigate metabolic and cardiovascular responses to walking in fructose-fed rats. Male Wistar rats were divided into control (C), sedentary fructose (SF) and walkingThe aim of this study was to investigate metabolic and cardiovascular responses to walking in fructose-fed rats. Male Wistar rats were divided into control (C), sedentary fructose (SF) and walking fructose (WF). Fructose-fed rats received D: -fructose (100 g/l). WF rats walked on a treadmill at constant load (0.3 km/h) during 1 h/day, 5 days/week for 8 weeks. Measurements of triglyceride concentrations, adipose tissue and glycemia were carried out together with insulin tolerance test to evaluate metabolic profile. Arterial pressure (AP) signals were directly recorded. Baroreflex sensitivity (BR) was evaluated by the reflex tachycardia (TR) and bradycardia (BR) to AP changes. The results showed that walking decreased the adipose tissue (SF: 6.5 ± 0.4; WF: 2.8 ± 0.1; C: 3.0 ± 0.3 g), blood triglyceride levels (SF: 291 ± 6.5; WF: 150 ± 8.1; C: 103 ± 4.5 mg/dl) and increased insulin sensitivity (SF: 2.5 ± 0.2; WF: 3.3 ± 0.32; C: 4.8 ± 0.4 %/min). Baroreflex sensitivity was improved in the WF group expressed by BR (SF: 0.75 ± 0.10; WF: 1.18 ± 0.10; C: 1.5 ± 0.14 ms/mmHg) and TR (SF: 0.80 ± 0.12; WF: 1.21 ± 0.10; C: 1.35 ± 0.11 ms/mmHg), as well as when verified by the alpha index. Although the WF group showed decreased AP when compared with the SF group, the values still enhanced in relation to C rats (SF: 137 ± 2; WF: 129 ± 1; C: 115 ± 6 mmHg). Our findings allow a better understanding of the effects of walking, a low-intensity exercise training, on the hemodynamic and metabolic aspects of male rats with metabolic syndrome and indicate that walking seems to be particularly effective in treating metabolic disturbances in this model.

• Noninvasive assessment of normality of V (D)/V (T) in clinical cardiopulmonary exercise testing utilizing incremental cycle ergometry.

  Authors: Michael A Roman, James D Casaburi, Janos Porszasz, Richard Casaburi

  European journal of applied physiology.

  Dead space to tidal volume ratio (V (D)/V (T)), a measure of pulmonary gas exchange efficiency, cannot be accurately calculated without arterial blood sampling. We sought to determine, in patientsDead space to tidal volume ratio (V (D)/V (T)), a measure of pulmonary gas exchange efficiency, cannot be accurately calculated without arterial blood sampling. We sought to determine, in patients presenting for diagnostic cardiopulmonary exercise tests, whether there are ranges of the ratio of exhaled ventilation to carbon dioxide output (V (E)/VCO(2)) measured at the lactate threshold that are highly predictive of normality or abnormality of exercise V (D)/V (T) (below or above 0.3) and whether other demographic or physiologic variables aid in this prediction. We reviewed 691 incremental cycle ergometer cardiopulmonary exercise tests featuring breath-by-breath gas exchange measurement and serial arterial blood sampling that were performed for patients with a range of disorders. When V (E)/VCO(2) at the lactate threshold was ≤28, 96 % of subjects had normal V (D)/V (T). For V (E)/VCO(2) 29-32, V (D)/V (T) was normal in 83 % of cases. V (E)/VCO(2) of 33-38 provided no useful information; V (D)/V (T) was normal and abnormal in 50 % of cases each. When V (E)/VCO(2) was ≥39, V (D)/V (T) was abnormal in 87 % of cases. For V (E)/VCO(2) ≥ 39, when FEV(1)/VC was <70 %, V (D)/V (T) was abnormal in 95 % of cases. End-tidal PCO(2) was of no help in distinguishing V (D)/V (T) normality in any V (E)/VCO(2) range. Our results reveal that certain values of V (E)/VCO(2) at LT (V (E)/VCO(2) ≤ 28 and V (E)/VCO(2) ≥ 39), but not others (V (E)/VCO(2) 29-32 and especially V (E)/VCO(2) of 33-38), can be helpful in determining normality of V (D)/V (T) during exercise in patients presenting for cardiopulmonary exercise testing.

• The effect of 12 weeks of resistance training on hormones of bone formation in young sedentary women.

  Authors: Mehrzad Moghadasi, Sadri Siavashpour

  European journal of applied physiology.

  Physical activity has been proposed as one strategy to enhance bone mineral acquisition; however, the basic mechanisms of this effect are not fully understood. The purpose of this study was toPhysical activity has been proposed as one strategy to enhance bone mineral acquisition; however, the basic mechanisms of this effect are not fully understood. The purpose of this study was to investigate the effect of 12 weeks of resistance training on hormones of bone formation in young sedentary women. Twenty sedentary females (aged 25.3 ± 3.2 years; ±SD) volunteered to participate in this study. The subjects were randomly assigned to a training group (n = 10) or control group (n = 10). Subjects executed eight resistance exercises selected to stress the major muscle groups in the following order: chest press, leg extension, shoulder press, leg curls, latissimus pull down, leg press, arm curls, and triceps extension. Resistance training consisted of 50-60 min of circuit weight training per day, 3 days a week, for 12 weeks. This training was circularly performed in eight stations and included two to four sets with 8-12 maximal repetitions at 65-80 % of one-repetition maximum in each station. After 12 weeks, the training group had a significant increase (P < 0.05) in the growth hormone, estrogen, parathyroid hormone and testosterone compared to the control group. The results showed that insulin-like growth factor I levels did not change significantly in response to resistance training. In conclusion, the results suggest that resistance training with specific intensity and duration utilized in this study increases the hormones of bone formation in young sedentary women.

• Effects of hypoxia on cerebral and muscle haemodynamics during knee extensions in healthy subjects.

  Authors: Paulo Sergio Chagas Gomes, Cristiane Matsuura, Yagesh N Bhambhani

  European journal of applied physiology.

  A hypoxic model was used to investigate changes in localized cerebral and muscle haemodynamics during knee extension (KE) in healthy individuals. Thirty-one young healthy volunteers performed one setA hypoxic model was used to investigate changes in localized cerebral and muscle haemodynamics during knee extension (KE) in healthy individuals. Thirty-one young healthy volunteers performed one set of KE until failure under hypoxia (14 % O(2)) or normoxia (21 % O(2)) at 50, 75 or 100 % of 1 repetition maximum, in random order, on three occasions. Prefrontal cerebral and vastus lateralis muscle oxygenation and blood volume (Cox, Mox, Cbv and Mbv, respectively) were recorded simultaneously by near-infrared spectroscopy. Hypoxia induced significant declines in Cox [-0.017 ± 0.016 optical density (OD) units] and Mox (-0.014 ± 0.026 OD units) and increases in Cbv (0.017 ± 0.027 OD units) and Mbv (0.016 ± 0.023 OD units) at rest. Hypoxia significantly reduced total work (TW) performed during KE at each exercise intensity. Cox, Cbv, Mox, and Mbv changes during KE did not differ between normoxia and hypoxia. Correlations between TW done and Cox changes under normoxia (r = 0.04, p = 0.182) and hypoxia (r = 0.05, p = 0.122) were not significant. However, TW was significantly correlated with Mox under both normoxia (R (2) = 0.24, p = 0.000) and hypoxia (R (2) = 0.15, p = 0.004). Since changes in Cox and Mox reflect alterations in the balance between oxygen delivery and extraction in these tissues, which, in the brain, is an index of neuronal activation, we conclude that: (1) limitation of KE performance was mediated peripherally under both normoxia and hypoxia, with no additional effect of hypoxia, and (2) because of the low common variance with Mox additional intramuscular factors likely play a role in limiting KE performance.

• The influence of vibration type, frequency, body position and additional load on the neuromuscular activity during whole body vibration.

  Authors: Ramona Ritzmann, Albert Gollhofer, Andreas Kramer

  European journal of applied physiology.

  This study aimed to assess the influence of different whole body vibration (WBV) determinants on the electromyographic (EMG) activity during WBV in order to identify those training conditions thatThis study aimed to assess the influence of different whole body vibration (WBV) determinants on the electromyographic (EMG) activity during WBV in order to identify those training conditions that cause highest neuromuscular responses and therefore provide optimal training conditions. In a randomized cross-over study, the EMG activity of six leg muscles was analyzed in 18 subjects with respect to the following determinants: (1) vibration type (side-alternating vibration (SV) vs. synchronous vibration (SyV), (2) frequency (5-10-15-20-25-30 Hz), (3) knee flexion angle (10°-30°-60°), (4) stance condition (forefoot vs. normal stance) and (5) load variation (no extra load vs. additional load equal to one-third of the body weight). The results are: (1) neuromuscular activity during SV was enhanced compared to SyV (P < 0.05); (2) a progressive increase in frequency caused a progressive increase in EMG activity (P < 0.05); (3) the EMG activity was highest for the knee extensors when the knee joint was 60° flexed (P < 0.05); (4) for the plantar flexors in the forefoot stance condition (P < 0.05); and (5) additional load caused an increase in neuromuscular activation (P < 0.05). In conclusion, large variations of the EMG activation could be observed across conditions. However, with an appropriate adjustment of specific WBV determinants, high EMG activations and therefore high activation intensities could be achieved in the selected muscles. The combination of high vibration frequencies with additional load on an SV platform led to highest EMG activities. Regarding the body position, a knee flexion of 60° and forefoot stance appear to be beneficial for the knee extensors and the plantar flexors, respectively.

• Relevance of hand dominance to the bilateral deficit phenomenon.

  Authors: Andrew Cornwell, Nazareth Khodiguian, Eun Jung Yoo

  European journal of applied physiology.

  During maximal voluntary contractions, the sum of forces exerted by homonymous muscles when activated unilaterally (UL) is, typically, larger than the sum of forces when activated bilaterally (BL).During maximal voluntary contractions, the sum of forces exerted by homonymous muscles when activated unilaterally (UL) is, typically, larger than the sum of forces when activated bilaterally (BL). This phenomenon is known as the bilateral deficit (BLD). Our purpose was to determine if the dominant limb would be inhibited to a greater degree in the BL condition, thereby reducing any disparity in force output between the limbs. Maximum voluntary handgrip strength was measured in 40 left-handed and 40 right-handed individuals under both BL and UL conditions. The right-handers displayed 10.4 % greater right hand strength in both conditions; the left-handers exhibited 5.5 % greater left hand strength in the UL and 4.3 % in the BL condition. A BLD (-1.30 %) was present in the left-handed group only but a reduction in the force disparity between the hands was not evident. It was observed, however, that seven individuals from each group exhibited greater UL force with their non-dominant hand. Accordingly, we re-analyzed the data after rearranging the groups based on unilateral hand grip strength dominance. A significant reduction in force disparity between the hands occurred for the left-handed group only, the result of a significant inhibition of the stronger left hand. A trend towards a similar reduction occurred for the right-handers because of a significant force reduction of the stronger right hand. Consequently, it appears that for maximum handgrip contractions, the BLD may be related to preferential inhibition of the stronger hand, especially for individuals who are left-hand-strength-dominant in terms of unilateral force output.

• The influence of rowing-related postures upon respiratory muscle pressure and flow generating capacity.

  Authors: Lisa A Griffiths, Alison K McConnell

  European journal of applied physiology.

  During the rowing stroke, the respiratory muscles are responsible for postural control, trunk stabilisation, generation/transmission of propulsive forces and ventilation (Bierstacker et al. in Int JDuring the rowing stroke, the respiratory muscles are responsible for postural control, trunk stabilisation, generation/transmission of propulsive forces and ventilation (Bierstacker et al. in Int J Sports Med 7:73-79, 1986; Mahler et al. in Med Sci Sports Exerc 23:186-193, 1991). The challenge of these potentially competing requirements is exacerbated in certain parts of the rowing stroke due to flexed (stroke 'catch') and extended postures (stroke 'finish'). The purpose of this study was to assess the influence of the postural role of the trunk muscles upon pressure and flow generating capacity, by measuring maximal respiratory pressures, flows, and volumes in various seated postures relevant to rowing. Eleven male and five female participants took part in the study. Participants performed two separate testing sessions using two different testing protocols. Participants performed either maximal inspiratory or expiratory mouth pressure manoeuvres (Protocol 1), or maximal flow volume loops (MFVLs) (Protocol 2), whilst maintaining a variety of specified supported or unsupported static rowing-related postures. Starting lung volume was controlled by initiating the test breath in the upright position. Respiratory mouth pressures tended to be lower with recumbency, with a significant decrease in P (Emax) in unsupported recumbent postures (3-9 % compared to upright seated; P = 0.036). There was a significant decrease in function during dynamic manoeuvres, including PIF (5-9 %), FVC (4-7 %) and FEV(1) (4-6 %), in unsupported recumbent postures (p < 0.0125; Bonferroni corrected). Thus, respiratory pressure and flow generating capacity tended to decrease with recumbency; since lung volumes were standardised, this may have been, at least in part, influenced by the postural co-contraction of the trunk muscles.

• Isometric strength training lowers the O(2) cost of cycling during moderate-intensity exercise.

  Authors: Jerzy A Zoladz, Zbigniew Szkutnik, Joanna Majerczak, Marcin Grandys, Krzysztof Duda, Bruno Grassi

  European journal of applied physiology.

  The effect of maximal voluntary isometric strength training of knee extensor muscles on pulmonary V'O(2) on-kinetics, the O(2) cost of cycling and peak oxygen uptake (V'O(2peak)) in humans wasThe effect of maximal voluntary isometric strength training of knee extensor muscles on pulmonary V'O(2) on-kinetics, the O(2) cost of cycling and peak oxygen uptake (V'O(2peak)) in humans was studied. Seven healthy males (mean ± SD, age 22.3 ± 2.0 years, body weight 75.0 ± 9.2 kg, V'O(2peak) 49.5 ± 3.8 ml kg(-1) min(-1)) performed maximal isometric strength training lasting 7 weeks (4 sessions per week). Force during maximal voluntary contraction (MVC) increased by 15 % (P < 0.001) after 1 week of training, and by 19 % (P < 0.001) after 7 weeks of training. This increase in MVC was accompanied by no significant changes in the time constant of the V'O(2) on-kinetics during 6 min of moderate and heavy cycling intensities. Strength training resulted in a significant decrease (by ~7 %; P < 0.02) in the amplitude of the fundamental component of the V'O(2) on-kinetics, and therefore in a lower O(2) cost of cycling during moderate cycling intensity. The amplitude of the slow component of V'O(2) on-kinetics during heavy cycling intensity did not change with training. Training had no effect on the V'O(2peak), whereas the maximal power output reached at V'O(2peak) was slightly but significantly increased (P < 0.05). Isometric strength training rapidly (i.e., after 1 week) decreases the O(2) cost of cycling during moderate-intensity exercise, whereas it does not affect the amplitude of the slow component of the V'O(2) on-kinetics during heavy-intensity exercise. Isometric strength training can have beneficial effects on performance during endurance events.

• Exercise-induced muscle damage from bench press exercise impairs arm cranking endurance performance.

  Authors: Gregory G Doncaster, Craig Twist

  European journal of applied physiology.

  The effects of exercise-induced muscle damage (EIMD) on the physiological, metabolic and perceptual responses during upper body arm cranking exercise are unknown. Nine physically active maleThe effects of exercise-induced muscle damage (EIMD) on the physiological, metabolic and perceptual responses during upper body arm cranking exercise are unknown. Nine physically active male participants performed 6 min of arm cranking exercise at ventilatory threshold (VT), followed by a time to exhaustion (TTE) trial at a workload corresponding to 80 % of the difference between VT and [Formula: see text] 48 h after bench pressing exercise (10 × 6 repetitions at 70 % one repetition maximum) or 20 min sitting (control). Reductions in isokinetic strength and increased muscle soreness of the elbow flexors and extensors were evident at 24 and 48 h after bench pressing exercise (P < 0.05). Despite no change in [Formula: see text], [Formula: see text], HR and blood lactate concentration ([Bla]) between conditions (P > 0.05), rating of perceived exertion (RPE) was higher during the 6 min arm cranking after bench pressing exercise compared to the control condition (P < 0.05). TTE was reduced in the treatment condition (207.2 ± 91.9 cf. 293.4 ± 75.6 s; P < 0.05), as were end [Formula: see text] (P < 0.05) and [Bla] at 0, 5 and 10 min after exercise (P < 0.05). RPE during the TTE trial was higher after bench pressing (P < 0.05), although end RPE was not different between conditions (P > 0.05). This study provides evidence that EIMD caused by bench pressing exercise increases the sense of effort during arm cranking exercise that leads to a reduced exercise tolerance. The findings have implications for individuals participating in concurrent endurance and resistance training of the upper body.

• Influence of acute dietary nitrate supplementation on 50 mile time trial performance in well-trained cyclists.

  Authors: Daryl P Wilkerson, Giles M Hayward, Stephen J Bailey, Anni Vanhatalo, Jamie R Blackwell, Andrew M Jones

  European journal of applied physiology.

  Dietary nitrate supplementation has been reported to improve short distance time trial (TT) performance by 1-3 % in club-level cyclists. It is not known if these ergogenic effects persist in longerDietary nitrate supplementation has been reported to improve short distance time trial (TT) performance by 1-3 % in club-level cyclists. It is not known if these ergogenic effects persist in longer endurance events or if dietary nitrate supplementation can enhance performance to the same extent in better trained individuals. Eight well-trained male cyclists performed two laboratory-based 50 mile TTs: (1) 2.5 h after consuming 0.5 L of nitrate-rich beetroot juice (BR) and (2) 2.5 h after consuming 0.5 L of nitrate-depleted BR as a placebo (PL). BR significantly elevated plasma [NO(2) (-)] (BR: 472 ± 96 vs. PL: 379 ± 94 nM; P < 0.05) and reduced completion time for the 50 mile TT by 0.8 % (BR: 136.7 ± 5.6 vs. PL: 137.9 ± 6.4 min), which was not statistically significant (P > 0.05). There was a significant correlation between the increased post-beverage plasma [NO(2) (-)] with BR and the reduction in TT completion time (r = -0.83, P = 0.01). Power output (PO) was not different between the conditions at any point (P > 0.05) but oxygen uptake ([Formula: see text]O(2)) tended to be lower in BR (P = 0.06), resulting in a significantly greater PO/[Formula: see text]O(2) ratio (BR: 67.4 ± 5.5 vs. PL: 65.3 ± 4.8 W L min(-1); P < 0.05). In conclusion, acute dietary supplementation with beetroot juice did not significantly improve 50 mile TT performance in well-trained cyclists. It is possible that the better training status of the cyclists in this study might reduce the physiological and performance response to NO(3) (-) supplementation compared with the moderately trained cyclists tested in earlier studies.

• Heat acclimation decreased oxidative DNA damage resulting from exposure to high heat in an occupational setting.

  Authors: Yung-Kai Huang, Che-Wei Lin, Chen-Chen Chang, Pai-Fen Chen, Chien-Jen Wang, Yu-Mei Hsueh, Hung-Che Chiang

  European journal of applied physiology.

  Heat acclimation is a physiologically and biochemically adapted process when species transition from one environmental temperature to one of the increased temperature. There is very limitedHeat acclimation is a physiologically and biochemically adapted process when species transition from one environmental temperature to one of the increased temperature. There is very limited epidemiological evidence on the heat-related impacts during exposure to extremely high heat in an occupational environment. This study sought to identify a potential biomarker of heat acclimation and the burden of heat on the body. The aim of this study was to elucidate oxidative DNA damage and heat acclimation through a self-comparison study design in navy boiler tenders, subjects exposed to extremely high heat in an occupational setting. Fifty-eight male soldiers who work in a boiler room were recruited for this study. The subjects were initially assessed with a health examination and body composition assessment before sailing. In order to compare the within-subject differences before and after heat exposure, the index-related heat exposure was collected before and after a routine 5-h work shift and 7-day sailing. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), a useful marker of oxidative DNA damage was the measurement by liquid chromatography/tandem mass spectrometry. The median of the change in urinary 8-OHdG was 0.78 μg/g creatinine, as the urinary 8-OHdG after sailing was significantly higher than before sailing (p < 0.01). The urinary 8-OHdG was significantly decreased in heat-acclimated boiler tenders. Oxidative DNA damage was significantly decreased in heat-acclimated subjects. Urinary 8-OHdG can be used as a biomarker to assess the effect of heat stress as a result of occupational exposure to extremely high heat conditions.

• The magnitude and duration of post-exercise hypotension after land and water exercises.

  Authors: Elmarie Terblanche, Aletta M E Millen

  European journal of applied physiology.

  The objective of the study was to determine and compare the magnitude and duration of post-exercise hypotension (PEH) during free-living conditions after an acute session of concurrent water and landThe objective of the study was to determine and compare the magnitude and duration of post-exercise hypotension (PEH) during free-living conditions after an acute session of concurrent water and land exercise in individuals with prehypertension and hypertension. Twenty-one men and women (aged 52 ± 10 years) volunteered for the study. Participants completed a no exercise control session, a water exercise session and a land exercise session in random order. After all three sessions, participants underwent 24-h monitoring using an Ergoscan ambulatory BP monitoring device. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were monitored to determine changes from resting values after each session and to compare the PEH responses between land and water exercises. During daytime, both land and water exercises resulted in significantly lower SBP (12.7 and 11.3 mmHg) compared to the control session (2.3 mmHg). The PEH response lasted for 24 h after land exercise and 9 h after water exercise. There was no difference in the daytime DBP for the three treatments (P > 0.05). Although all three groups showed significant reductions during nighttime, both exercise treatments showed greater nocturnal falls in BP than the control treatment. This is the first study to show that the magnitude of the PEH response is similar for land and water exercises, although the duration of PEH may be longer for land exercise. These results suggest that water exercise is a safe alternative exercise modality for individuals with suspected and known hypertension.

• Time course of arterial remodelling in diameter and wall thickness above and below the lesion after a spinal cord injury.

  Authors: Dick H J Thijssen, Patricia C E De Groot, Arne van den Bogerd, Matthijs Veltmeijer, N Timothy Cable, Daniel J Green, Maria T E Hopman

  European journal of applied physiology.

  Physical inactivity in response to a spinal cord injury (SCI) represents a potent stimulus for conduit artery remodelling. Changes in conduit artery characteristics may be induced by the localPhysical inactivity in response to a spinal cord injury (SCI) represents a potent stimulus for conduit artery remodelling. Changes in conduit artery characteristics may be induced by the local effects of denervation (and consequent extreme inactivity below the level of the lesion), and also by systemic adaptations due to whole body inactivity. Therefore, we assessed the time course of carotid (i.e. above lesion) and common femoral artery (i.e. below lesion) lumen diameter and wall thickness across the first 24 weeks after an SCI. Eight male subjects (mean age 35 ± 14 years) with a traumatic motor complete spinal cord lesion between T5 and L1 (i.e. paraplegia) were included. Four subjects were measured across the first 6 weeks after SCI, whilst another four subjects were measured from 8 until 24 weeks after SCI. Ultrasound was used to examine the diameter and wall thickness from the carotid and common femoral arteries. Carotid artery diameter did not change across 24 weeks, whilst femoral artery diameter stabilised after the rapid initial decrease during the first 3 weeks after the SCI. Carotid and femoral artery wall thickness showed no change during the first few weeks, but increased both between 6 and 24 weeks (P < 0.05). In conclusion, SCI leads to a rapid and localised decrease in conduit artery diameter which is isolated to the denervated and paralyzed region, whilst wall thickness gradually increases both above and below the lesion. This distinct time course of change in conduit arterial diameter and wall thickness suggests that distinct mechanisms may contribute to these adaptations.

• Hydration assessment using the cardiovascular response to standing.

  Authors: Samuel N Cheuvront, Brett R Ely, Robert W Kenefick, Mark J Buller, Nisha Charkoudian, Michael N Sawka

  European journal of applied physiology.

  The cardiovascular response to standing (sit-to-stand change in heart rate; SSΔHR) is commonly employed as a screening tool to detect hypohydration (body water deficit). No study has systematicallyThe cardiovascular response to standing (sit-to-stand change in heart rate; SSΔHR) is commonly employed as a screening tool to detect hypohydration (body water deficit). No study has systematically evaluated SSΔHR cut points using different magnitudes or different types of controlled hypohydration. The objective of this study was to determine the diagnostic accuracy of the often proposed 20 b/min SSΔHR cut point using both hypertonic and isotonic models of hypohydration. Thirteen healthy young adults (8M, 5F) underwent three bouts of controlled hypohydration. The first bout used sweating to elicit large losses of body water (mass) (>3 % sweat). The second two bouts were matched to elicit 3 % body mass losses (3 % diuretic; 3 % sweat). A euhydration control trial (EUH) was paired with each hypohydration trial for a total of six trials. Heart rate was assessed after 3-min sitting and after 1-min standing during all trials. SSΔHR was compared among trials, and receiver operator characteristic curve analysis was used to determine diagnostic accuracy of the 20 b/min SSΔHR cut point. Volunteers lost 4.5 ± 1.1, 3.0 ± 0.6, and 3.2 ± 0.6 % body mass during >3 % sweat, 3 % diuretic, and 3 % sweat trials, respectively. SSΔHR (b/min) was 9 ± 8 (EUH), 20 ± 12 (>3 % sweat; P < 0.05 vs. EUH), 17 ± 7 (3 % diuretic; P < 0.05 vs. EUH), and 13 ± 11 (3 % sweat). The 20 beats/min cut point had high specificity (90 %) but low sensitivity (44 %) and overall diagnostic accuracy of 67 %. SSΔHR increased significantly in response to severe hypertonic hypohydration and moderate isotonic hypohydration, but not moderate hypertonic hypohydration. However, the 20 beats/min cut point afforded only marginal diagnostic accuracy.

• Altered ventriculo-arterial coupling during exercise in athletes releasing biomarkers after endurance running.

  Authors: Anders Sahlén, Kambiz Shahgaldi, Philip Aagaard, Aristomenis Manouras, Reidar Winter, Frieder Braunschweig

  European journal of applied physiology.

  Exercise can lead to release of biomarkers such as cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP), a poorly understood phenomenon proposed to especially occur withExercise can lead to release of biomarkers such as cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP), a poorly understood phenomenon proposed to especially occur with high-intensity exercise in less trained subjects. We hypothesised that haemodynamic perturbations during exercise are larger in athletes with cTnT release, and studied athletes with detectable cTnT levels after an endurance event (HIGH; n = 16; 46 ± 9 years) against matched controls whose levels were undetectable (LOW; n = 11; 44 ± 7 years). Echocardiography was performed at rest and at peak supine bicycle exercise stress. Left ventricular (LV) end-systolic elastance (E (LV) a load-independent measure of LV contractility), effective arterial elastance (E (A) a lumped index of arterial load) and end-systolic meridional wall stress were calculated from cardiac dimensions and brachial blood pressure. Efficiency of cardiac work was judged from the ventriculo-arterial coupling ratio (E (A)/E (LV): optimal range 0.5-1.0). While subgroups had similar values at rest, we found ventriculo-arterial mismatch during exercise in HIGH subjects [0.47 (0.39-0.58) vs. LOW: 0.73 (0.62-0.83); p < 0.01] due to unopposed increase in E (LV) (p < 0.05). In LOW subjects, a greater increase occurred in E (A) during exercise (+81 ± 67 % vs. HIGH: +39 ± 32 %; p = 0.02) which contributed to a maintained coupling ratio. Subjects with higher baseline NT-proBNP had greater systolic wall stress during exercise (R (2) = 0.39; p < 0.01) despite no correlation at rest (p = ns). In conclusion, athletes with exercise-induced biomarker release exhibit ventriculo-arterial mismatch during exercise, suggesting non-optimal cardiac work may contribute to this phenomenon.

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