Klavs Madsen - Academia.edu (original) (raw)

Papers by Klavs Madsen

Journal of Applied Physiology

The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contrac... more The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contractile properties before and during recovery from fatigue in the rat extensor digitorum longus muscle. Fatiguing contractions (60 Hz, 150 ms/s for 4 min) induced a reduction of the SR Ca(2+) release rate to 66% that persisted for 1 h, followed by a gradual recovery to 87% of prefatigue release rate at 3 h recovery. Tetanic force and rate of force development (+dF/dt) and relaxation (-dF/dt) were depressed by approximately 80% after stimulation. Recovery occurred in two phases: an initial phase, in which during the first 0.5-1 h the metabolic state recovered to resting levels, and a slow phase from 1-3 h characterized by a rather slow recovery of the mechanical properties. The recovery of SR Ca(2+) release rate was closely correlated to +dF/dt during the slow phase of recovery (r(2) = 0.51; P < 0.05). Despite a slowing of the relaxation rate, we did not find any significant alterations i...

The American journal of physiology

The purpose of this study was to measure resting muscle and blood antioxidant status in untrained... more The purpose of this study was to measure resting muscle and blood antioxidant status in untrained (n = 8) and jump-trained (n = 8) humans and to evaluate free radical-mediated muscle damage after a strenuous jump test consisting of six bouts of 30-s continuous jumping separated by 2 min of rest. Resting muscle antioxidant activities [superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GR), and manganese SOD] were significantly higher in jump-trained compared with untrained subjects. Blood antioxidant enzyme activities and muscle catalase, however, were not different between the two groups. Creatine kinase activities increased significantly (P < 0.0001) after the jump test in untrained individuals, but remained unchanged in the jump trained. Plasma and muscle malonaldehyde (MDA) after the jump test were not significantly different from rest. These data suggest that jump training is associated with elevated activities of SOD and the coupled enzymes GPX ...

The American journal of physiology

The purpose of this study was to evaluate the relationship between mitochondrial Ca2+ concentrati... more The purpose of this study was to evaluate the relationship between mitochondrial Ca2+ concentration and the respiratory control index (RCI; state III/state IV) in isolated mitochondria before and after exhaustive exercise at 75% of maximal O2 consumption. Muscle biopsies of 100-150 mg from 12 moderately trained men were sampled at rest, immediately after exercise, and 30 or 60 min after exercise. The mitochondrial Ca2+ content after exhaustive exercise was significantly higher than the preexercise level [15.1 (range 39.4) vs. 11.6 (range 6.5) nmol/mg protein, respectively; P < 0.05], and RCI increased from 11.6 (range 14.4) at rest to 13.7 (range 15.0) at exhaustion (P < 0.05). After 60 min of recovery, the mitochondrial Ca2+ content was still high [18.8 (range 29.9) nmol/mg protein], but the RCI value was significantly depressed because of the increased state IV value and, in fact, was lower than the preexercise value [8.6 (range 5.1); P < 0.05]. Our results show that the ...

International journal of sport nutrition and exercise metabolism

This trial aimed to examine the effect of whey protein hydrolysate intake before and after exerci... more This trial aimed to examine the effect of whey protein hydrolysate intake before and after exercise sessions on endurance performance and recovery in elite orienteers during a training camp. Eighteen elite orienteers participated in a randomized controlled intervention trial during a 1-week training camp (13 exercise sessions). Half of the runners (PRO-CHO) ingested a protein drink before (0.3 g kg-1) and a protein-carbohydrate drink after (0.3 g protein kg-1 and 1 g carbohydrate kg-1) each exercise session. The others ingested energy and time-matched carbohydrate drinks (CHO). A 4-km run-test with 20 control points was performed before and on the last day of the intervention. Blood and saliva were obtained in the mornings, before and after run-tests and after the last training session. During the intervention questionnaires were fulfilled regarding psychological sense of performance capacity and motivation. PRO-CHO, and not CHO, improved performance in the 4-km run-test (interactio...

Acta Physiologica Scandinavica, 1994

Thirty-nine moderately endurance trained males increased their normal training programme of 2.2 h... more Thirty-nine moderately endurance trained males increased their normal training programme of 2.2 h week-' with an average training intensity of 65 % of maximum heart rate (HR,,,) to 2.7 h week-' and a mean intensity of 78%, of HR,,,. Performance tests and measurements of the total concentrations of Na,K-ATPase (3H-ouabain binding) and Ca-ATPase, fibre type distribution and fibre area were performed in biopsies from the vastus lateralis muscle before and after increased training. The 6 weeks of training elevated VoPmax from 54.9 3.1 to 58.3 k 3.0 m l 0 , min-' kg-' ( P < 0.0001). Exercise time to exhaustion at 86% of VoZmax (pre-training) increased from 35 k 8 to 61 17 min ( P < 0.0001). The concentration of Ca-ATPase was unaffected by the intensified training (6.74+ 1.03 vs. 6.68+ 1.07 nmol g wet wt-l), but the concentration of Na,K-ATPase increased from 307+43 to 354+ 59 pmol g wet wt'.' (P < 0.0001). The relative distribution of FT-fibres was correlated with the concentration of Ca-ATPase (r = 0.72, P < 0.0001). The data support the view that intensive training induces an upregulation of the concentration of skeletal muscle Na,K-ATPase, but no change in the total capacity for reaccumulation of Ca2+ into the SR. There was no correlation between the concentrations of Na,K-ATPase, Ca-ATPase and indices of endurance performance.

The Journal of sports medicine and physical fitness, Jan 9, 2014

Aim: The aim of the present study was to examine the physical demands placed on male elite team h... more Aim: The aim of the present study was to examine the physical demands placed on male elite team handball (TH) players in relation to playing position. Methods: Male elite TH field players were evaluated during match-play over a six season time span using physiological measurements and by subsequent physical testing. Results: Mean heart rate and relative workload during match-play (n=41) were 163±5 beats·min-1 (group means±SD) and 70.9±6.0 % of VO2-max, respectively. Relative workload was lower (p<0.01) in the second half vs. the first (66.3±5.9 % vs. 75.4±5.6 % of VO2-max). Post-match blood lactate concentration was 4.8±1.9 mM (range: 2.8-10.8 mM). Mean fluid loss was 0.81±0.41 l pr. match. Mean VO2-max was 5.18±0.66 l O2·min-1 corresponding to 57.0±4.1 ml O2·min-1·kg-1. Mean total running distance in the Yo-Yo intermittent recovery test (level 2) was 895±184 m (range: 520-1360 m), which was greater in wing players (975±123 m) than backcourt players (897±108 m) and pivots (827±26...

International journal of sports medicine, 2014

The present study evaluated the physical demands imposed on female elite team handball players in... more The present study evaluated the physical demands imposed on female elite team handball players in relation to playing position. Female elite team handball field players were examined during match-play over a 5-year period using video based computerized locomotion analysis of tournament matches. In addition, physiological measurements during match-play and in separate physical tests were carried out. A total distance of 4002±551 m (group means±SD) was covered per match with a total effective playing time of 50:42±5:50 min:s, while full-time players covered 4693±333 m. On average, each player (n=83) performed 663.8±99.7 activity changes per match, and the mean speed was 5.31±0.33 km · h(-1). High-intensity running constituted 0.8±0.5% of total effective playing time per match corresponding to 2.5±1.8% of the total distance covered. The amount of high-intensity running was reduced (p<0.05) 21.9% in the second half (44.9±16.8 m) compared to the first (57.5±21.3 m). Maximal oxygen upt...

International journal of sports medicine, 2013

The purpose of this study was to determine the physical demands and match-induced impairments in ... more The purpose of this study was to determine the physical demands and match-induced impairments in physical performance in male elite Team Handball (TH) players in relation to playing position. Male elite TH field players were closely observed during 6 competitive seasons. Each player (wing players: WP, pivots: PV, backcourt players: BP) was evaluated during match-play using video recording and subsequently performing locomotion match analysis. A total distance of 3 627±568 m (group means±SD) was covered per match with a total effective playing time (TPT) of 53:51±5:52 min:s, while full-time players covered 3 945±538 m. The mean speed was 6.40±1.01 km · h - 1. High-intensity running constituted only 1.7±0.9% of TPT per match corresponding to 7.9±4.9% of the total distance covered. An average of 1 482.4±312.6 activity changes per player (n=82) with 53.2±14.1 high-intensity runs were observed per match. Total distance covered was greater in BP (3 765±532 m) and WP (3 641±501 m) than PV ...

International journal of sports medicine, 2009

The present study examined the fatigue development in muscle mechanical properties with emphasis ... more The present study examined the fatigue development in muscle mechanical properties with emphasis on rapid force characteristics and neuromuscular activity in response to high level soccer match play. Young elite soccer players (n=9) were tested before (CON) and after (POST) a soccer match for maximal knee extensor and flexor isometric strength (MVC) and contractile rate of force development (RFD) with synchronous surface electromyography (EMG) recording. Furthermore, maximal vertical jump power and related parameters were assessed. Isometric knee extensor and flexor MVC decreased approximately 10% (p< or =0.01) along with a right-shift in the moment-time curve. RFD decreased approximately 9% (0-200 ms) for the knee flexors while there was a tendency towards reduced RFD during knee extension following soccer match play. Similar reductions were observed for some but not all selected EMG parameters during the MVC and RFD tests. Mechanical jump parameters generally remained unchanged...

Journal of Strength and Conditioning Research, 2015

Michalsik, LB, Madsen, K, and Aagaard, P. Technical match characteristics and influence of body a... more Michalsik, LB, Madsen, K, and Aagaard, P. Technical match characteristics and influence of body anthropometry on playing performance in male elite team handball. J Strength Cond Res 29 (2): 416-428, 2015-Modern team handball match-play imposes substantial physical and technical demands on elite players. However, only limited knowledge seems to exist about the specific working requirements in elite team handball. Thus, the purpose of this study was to examine the physical demands imposed on male elite team handball players in relation to playing position and body anthropometry. Based on continuous video recording of individual players during elite team handball match-play (62 tournament games, ;4 players per game), computerized technical match analysis was performed in male elite team handball players along with anthropometric measurements over a 6 season time span. Technical match activities were distributed in 6 major types of playing actions (shots, breakthroughs, fast breaks, tackles, technical errors, and defense errors) and further divided into various subcategories (e.g., hard or light tackles, type of shot, claspings, screenings, and blockings). Players showed 36.9 6 13.1 (group mean 6 SD) high-intense technical playing actions per match with a mean total effective playing time of 53.85 6 5.87 minutes. In offense, each player performed 6.0 6 5.2 fast breaks, received 34.5 6 21.3 tackles in total, and performed in defense 3.7 6 3.5 blockings, 3.9 6 3.0 claspings, and 5.8 6 3.6 hard tackles. Wing players (84.5 6 5.8 kg, 184.9 6 5.7 cm) were less heavy and smaller (p , 0.001) than backcourt players (94.7 6 7.1 kg, 191.9 6 5.4 cm) and pivots (99.4 6 6.2 kg, 194.8 6 3.6 cm). In conclusion, modern male elite team handball matchplay is characterized by a high number of short-term, high-intense intermittent technical playing actions. Indications of technical fatigue were observed. Physical demands differed between playing positions with wing players performing more fast breaks and less physical confrontations with opponent players than backcourt players and pivots. Body anthropometry seemed to have an important influence on playing performance because it is highly related to playing positions. The present observations suggest that male elite team handball players should implement more position-specific training regimens, while also focusing on anaerobic training and strength training.

Holloway GP, Thrush AB, Heigenhauser GJ, Tandon NN, Dyck DJ, Bonen A, Spriet LL. Skeletal muscle ... more Holloway GP, Thrush AB, Heigenhauser GJ, Tandon NN, Dyck DJ, Bonen A, Spriet LL. Skeletal muscle mitochondrial FAT/CD36 content and palmitate oxidation are not decreased in obese women. A reduction in fatty acid oxidation has been associated with lipid accumulation and insulin resistance in the skeletal muscle of obese individuals. We examined whether this decrease in fatty acid oxidation was attributable to a reduction in muscle mitochondrial content and/or a dysfunction in fatty acid oxidation within mitochondria obtained from skeletal muscle of age-matched, lean [body mass index (BMI) ϭ 23.3 Ϯ 0.7 kg/m 2 ] and obese women (BMI ϭ 37.6 Ϯ 2.2 kg/m 2 ). The mitochondrial marker enzymes citrate synthase (Ϫ34%), ␤-hydroxyacyl-CoA dehydrogenase (Ϫ17%), and cytochrome c oxidase (Ϫ32%) were reduced (P Ͻ 0.05) in obese participants, indicating that mitochondrial content was diminished. Obesity did not alter the ability of isolated mitochondria to oxidize palmitate; however, fatty acid oxidation was reduced at the whole muscle level by 28% (P Ͻ 0.05) in the obese. Mitochondrial fatty acid translocase (FAT/ CD36) did not differ in lean and obese individuals, but mitochondrial FAT/CD36 was correlated with mitochondrial fatty acid oxidation (r ϭ 0.67, P Ͻ 0.05). We conclude that the reduction in fatty acid oxidation in obese individuals is attributable to a decrease in mitochondrial content, not to an intrinsic defect in the mitochondria obtained from skeletal muscle of obese individuals. In addition, it appears that mitochondrial FAT/CD36 may be involved in regulating fatty acid oxidation in human skeletal muscle. obesity; mitochondria; fatty acid translocase/CD36; transport proteins

The Journal of Physiology, 2006

We hypothesized that suppression of endogenous testosterone blunts mRNA expression post strength ... more We hypothesized that suppression of endogenous testosterone blunts mRNA expression post strength training (ST). Twenty-two young men were randomized for treatment with the GnRH analogue goserelin (3.6 mg every 4 weeks) or placebo for a period of 12 weeks. The ST period of 8 weeks started at week 4. Strength test, blood sampling, muscle biopsies, and whole-body dual-energy X-ray absorptiometry (DXA) scan were performed at weeks 4 and 12. Muscle biopsies were taken during the final ST session (pre, post 4 h, and post 24 h). Resting serum testosterone decreased significantly (P < 0.01) in the goserelin group from 22.6 ± 1.6 (mean ± S.E.M.) to 2.0 ± 0.1 nmol l −1 (week 4), whereas it remained unchanged in the placebo group. An acute increase of serum testosterone was observed during the final ST session in the placebo group (P < 0.05), whereas a decreased response was observed in the goserelin group (P < 0.05). mRNA expression of IGF-IE(bc) and myogenin increased, while expression of myostatin decreased (P < 0.01); however, no differences were observed between the groups. Muscle strength and muscle mass showed a tendency to increase more in the placebo group than in the goserelin group (P = 0.05). In conclusion, despite blocked acute responses of testosterone and 10-to 20-fold lower resting levels in the goserelin group, ST resulted in a similar mRNA expression of myoD, myogenin, IGF-IE(abc), myostatin and androgen receptor as observed in the placebo group. Therefore, in the present study, the molecular events were the same, despite divergent muscle hypertrophy and strength gains.

Scandinavian Journal of Medicine & Science in Sports, 2007

The purpose of the present study was to determine the acute fatigue development in muscle mechani... more The purpose of the present study was to determine the acute fatigue development in muscle mechanical properties and neuromuscular activity in response to handball match play. Male elite handball players (n 5 10) were tested before and after a simulated handball match for maximal isometric strength [maximal voluntary contraction (MVC)] and rate of force development (RFD) with synchronous electromyography (EMG) recording, while maximal vertical jump parameters were assessed using force plate analysis. Quadriceps and hamstrings MVC and RFD decreased significantly post-match ( $ 10%, Po0.05 and $ 16-21%, Po0.05, respectively). During quadriceps, MVC mean EMG amplitude [mean average voltage (MAV)] decreased for the vastus lateralis (VL) and rectus femoris (RF) (21-42%, P 0.05), while MAV also decreased in the antagonist biceps femoris (BF) muscle (48-55%, Po0.01). During hamstring MVC, MAV was reduced in BF (31%, Po0.01). Maximum EMG amplitude during quadriceps MVC was reduced for the VL (28%, Po0.01) and the RF (5%, Po0.05). During hamstring MVC, maximum EMG was reduced for BF (21%, Po0.01). Post-match maximal jump height was reduced (5.2%, Po0.01), as was also work (6.8%, Po0.01), velocity of center of mass (2.4-4.0%, Po0.01) and RFD ( $ 30%, Po0.05). In conclusion, maximal (MVC) and rapid muscle force characteristics (RFD, impulse) were acutely affected concurrently with marked reductions in muscle EMG following handball match play, which may potentially lead to impaired functional performance.

Scandinavian Journal of Medicine & Science in Sports, 2007

of oxygen uptake in elite orienteers during cross-country running using telemetry. Scand J Med Sc... more of oxygen uptake in elite orienteers during cross-country running using telemetry. Scand J Med Sci Sports 1994 4: 234-238. 0 Munksgaard, 1994 Oxygen uptake (V0J was measured and economy calculated during running on a treadmill and during cross-country running in 14 male and 9 female orienteers using a telemetric system (K-2, Cosmed, Italy). The cross-country route comprised 3 parts: horizontal path running, horizontal running in light terrain and running in heavy terrain with obstacles and steep hills. Each subject accomplished the whole test route at a speed corresponding to 9625% of maximal speed and at maximal speed. The running time at maximal speed was 1923 min. The running economy was similar in treadmill and path running (21 1 2 10 vs 2102 14 ml . kg-' . km-I), but V,, per km increased in light and heavy terrain to 290+ 16 and 362t 18 ml . kg-l. km-I, respectively. There was no difference in running economy between men and women. The elite group (5 men and 3 women) demonstrated 5% better running economy than the sub-elite (9 men and 6 women) during running in light and heavy terrain, whereas no difference was seen during treadmill and path running. In conclusion, elite orienteers have better running economy in light and heavy terrain than sub-I elite orienteers. Several parameters measured during treadmill running under laboratory conditions can be used to predict performance in running competitions. Maximal oxygen uptake (VOlmax) and the fraction of V02max that can be utilized during running play important roles for the success in running competitions (1-3). Running velocity at the onset of blood lactate accumulation (VOBLA), determined from interpolation of the curve between velocity and blood lactate concentration also predicts distance running performance (4). Velocity at VO2,,, (VV02max), determined from extrapolation of the curve between running velocity and Vo2, has also been shown to predict performance in distance running (5). Furthermore, running economy, defined as the relationship between oxygen uptake and running speed, also plays an important role (6-9).

Scandinavian Journal of Medicine & Science in Sports, 2013

The effect of a whey protein- and carbohydrate (CHO)-enriched diet on the rate of muscle glycogen... more The effect of a whey protein- and carbohydrate (CHO)-enriched diet on the rate of muscle glycogen resynthesis after a soccer match was examined. Sixteen elite soccer players were randomly assigned to a group ingesting a diet rich in carbohydrates and whey protein [CHO, protein, and fat content was 71, 21, and 8E%, respectively; high content of carbohydrates and whey protein (HCP), n = 9] or a group ingesting a normal diet (55, 18, and 26E%; control [CON], n = 7) during a 48-h recovery period after a soccer match. CON and three additional players carried out a 90- and 60-min simulated match without body contacts (SIM90 and SIM60). Muscle glycogen was lowered (P &amp;amp;lt; 0.05) by 54, 48, 53, and 38% after the matches in CON, HCP, SIM90, and SIM60, respectively. Glycogen resynthesis during the first 48 h after the match was not different between CON and HCP, whereas glycogen resynthesis was slower (P &amp;amp;lt; 0.05) during the first 24 h after SIM60 than SIM90 (2.88 ± 0.84 vs 4.32 ± 0.54 mmol/kg dw/h). In HCP, glycogen content in type II muscle fibers was still lowered 48 h after the match. In conclusion, glycogen resynthesis 48 h after a soccer match is not elevated by ingestion of a HCP diet. Furthermore, glycogen resynthesis does not appear to be impaired by body contacts during a match.

Molecular and Cellular Biochemistry, 2013

Sarcoplasmic and t-tubule membrane proteins regulating sarcoplasmic Ca 2? concentration exhibit f... more Sarcoplasmic and t-tubule membrane proteins regulating sarcoplasmic Ca 2? concentration exhibit fibretype-dependent isoform expression, and play central roles in muscle contraction and relaxation. The purpose of this study was to evaluate the effects of in vitro electrical stimulation on the mRNA expression of components involved in Ca 2? regulation in oxidative and glycolytic skeletal muscle. The mRNA level of Ca 2? -ATPase (SERCA1, 2), calsequestrin (CASQ1, 2), ryanodine receptor (RyR1), and dihydropyridine receptor (Cacna1) was assessed in rat extensor digitorum longus (EDL) and soleus (SOL) muscles at 4 h of recovery following in vitro stimulations (either short intensive (SHO) 60 Hz, 5 min, or prolonged moderate (PRO) 20 Hz, 40 min). Stimulation induced acute regulation of the mRNA level of Ca 2? -regulating proteins in a manner that does not follow typical fibre-type-specific transitions. In general, stimulation decreased mRNA content of all proteins studied. Most prominent down-regulation was observed for Cacna1 (26 and 32 % after SHO and PRO, respectively, in SOL; 19 % after SHO in EDL). SERCA1, SERCA2, CASQ1, CASQ2, and RyR1 mRNA content also decreased significantly in both muscles relative to resting control. Of notice is that hexokinase II mRNA content was increased in EDL and unchanged in SOL underlining the specificity of the down-regulation of mRNA of Ca 2? regulatory proteins. The results demonstrate contraction-induced down-regulation of mRNAs for the main components of Ca 2? -regulating system in skeletal muscle. The down-regulation of both isoforms of SERCA and CASQ after a single electrical stimulation session suggests that adaptations to repeated stimulation involve further regulatory mechanisms in addition to acute mRNA responses.

Medicine & Science in Sports & Exercise, 2007

Medicine & Science in Sports & Exercise, 2002

Medicine & Science in Sports & Exercise, 1993

Medicine & Science in Sports & Exercise, 2006

Journal of Applied Physiology

The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contrac... more The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contractile properties before and during recovery from fatigue in the rat extensor digitorum longus muscle. Fatiguing contractions (60 Hz, 150 ms/s for 4 min) induced a reduction of the SR Ca(2+) release rate to 66% that persisted for 1 h, followed by a gradual recovery to 87% of prefatigue release rate at 3 h recovery. Tetanic force and rate of force development (+dF/dt) and relaxation (-dF/dt) were depressed by approximately 80% after stimulation. Recovery occurred in two phases: an initial phase, in which during the first 0.5-1 h the metabolic state recovered to resting levels, and a slow phase from 1-3 h characterized by a rather slow recovery of the mechanical properties. The recovery of SR Ca(2+) release rate was closely correlated to +dF/dt during the slow phase of recovery (r(2) = 0.51; P < 0.05). Despite a slowing of the relaxation rate, we did not find any significant alterations i...

The American journal of physiology

The purpose of this study was to measure resting muscle and blood antioxidant status in untrained... more The purpose of this study was to measure resting muscle and blood antioxidant status in untrained (n = 8) and jump-trained (n = 8) humans and to evaluate free radical-mediated muscle damage after a strenuous jump test consisting of six bouts of 30-s continuous jumping separated by 2 min of rest. Resting muscle antioxidant activities [superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GR), and manganese SOD] were significantly higher in jump-trained compared with untrained subjects. Blood antioxidant enzyme activities and muscle catalase, however, were not different between the two groups. Creatine kinase activities increased significantly (P < 0.0001) after the jump test in untrained individuals, but remained unchanged in the jump trained. Plasma and muscle malonaldehyde (MDA) after the jump test were not significantly different from rest. These data suggest that jump training is associated with elevated activities of SOD and the coupled enzymes GPX ...

The American journal of physiology

The purpose of this study was to evaluate the relationship between mitochondrial Ca2+ concentrati... more The purpose of this study was to evaluate the relationship between mitochondrial Ca2+ concentration and the respiratory control index (RCI; state III/state IV) in isolated mitochondria before and after exhaustive exercise at 75% of maximal O2 consumption. Muscle biopsies of 100-150 mg from 12 moderately trained men were sampled at rest, immediately after exercise, and 30 or 60 min after exercise. The mitochondrial Ca2+ content after exhaustive exercise was significantly higher than the preexercise level [15.1 (range 39.4) vs. 11.6 (range 6.5) nmol/mg protein, respectively; P < 0.05], and RCI increased from 11.6 (range 14.4) at rest to 13.7 (range 15.0) at exhaustion (P < 0.05). After 60 min of recovery, the mitochondrial Ca2+ content was still high [18.8 (range 29.9) nmol/mg protein], but the RCI value was significantly depressed because of the increased state IV value and, in fact, was lower than the preexercise value [8.6 (range 5.1); P < 0.05]. Our results show that the ...

International journal of sport nutrition and exercise metabolism

This trial aimed to examine the effect of whey protein hydrolysate intake before and after exerci... more This trial aimed to examine the effect of whey protein hydrolysate intake before and after exercise sessions on endurance performance and recovery in elite orienteers during a training camp. Eighteen elite orienteers participated in a randomized controlled intervention trial during a 1-week training camp (13 exercise sessions). Half of the runners (PRO-CHO) ingested a protein drink before (0.3 g kg-1) and a protein-carbohydrate drink after (0.3 g protein kg-1 and 1 g carbohydrate kg-1) each exercise session. The others ingested energy and time-matched carbohydrate drinks (CHO). A 4-km run-test with 20 control points was performed before and on the last day of the intervention. Blood and saliva were obtained in the mornings, before and after run-tests and after the last training session. During the intervention questionnaires were fulfilled regarding psychological sense of performance capacity and motivation. PRO-CHO, and not CHO, improved performance in the 4-km run-test (interactio...

Acta Physiologica Scandinavica, 1994

Thirty-nine moderately endurance trained males increased their normal training programme of 2.2 h... more Thirty-nine moderately endurance trained males increased their normal training programme of 2.2 h week-' with an average training intensity of 65 % of maximum heart rate (HR,,,) to 2.7 h week-' and a mean intensity of 78%, of HR,,,. Performance tests and measurements of the total concentrations of Na,K-ATPase (3H-ouabain binding) and Ca-ATPase, fibre type distribution and fibre area were performed in biopsies from the vastus lateralis muscle before and after increased training. The 6 weeks of training elevated VoPmax from 54.9 3.1 to 58.3 k 3.0 m l 0 , min-' kg-' ( P < 0.0001). Exercise time to exhaustion at 86% of VoZmax (pre-training) increased from 35 k 8 to 61 17 min ( P < 0.0001). The concentration of Ca-ATPase was unaffected by the intensified training (6.74+ 1.03 vs. 6.68+ 1.07 nmol g wet wt-l), but the concentration of Na,K-ATPase increased from 307+43 to 354+ 59 pmol g wet wt'.' (P < 0.0001). The relative distribution of FT-fibres was correlated with the concentration of Ca-ATPase (r = 0.72, P < 0.0001). The data support the view that intensive training induces an upregulation of the concentration of skeletal muscle Na,K-ATPase, but no change in the total capacity for reaccumulation of Ca2+ into the SR. There was no correlation between the concentrations of Na,K-ATPase, Ca-ATPase and indices of endurance performance.

The Journal of sports medicine and physical fitness, Jan 9, 2014

Aim: The aim of the present study was to examine the physical demands placed on male elite team h... more Aim: The aim of the present study was to examine the physical demands placed on male elite team handball (TH) players in relation to playing position. Methods: Male elite TH field players were evaluated during match-play over a six season time span using physiological measurements and by subsequent physical testing. Results: Mean heart rate and relative workload during match-play (n=41) were 163±5 beats·min-1 (group means±SD) and 70.9±6.0 % of VO2-max, respectively. Relative workload was lower (p<0.01) in the second half vs. the first (66.3±5.9 % vs. 75.4±5.6 % of VO2-max). Post-match blood lactate concentration was 4.8±1.9 mM (range: 2.8-10.8 mM). Mean fluid loss was 0.81±0.41 l pr. match. Mean VO2-max was 5.18±0.66 l O2·min-1 corresponding to 57.0±4.1 ml O2·min-1·kg-1. Mean total running distance in the Yo-Yo intermittent recovery test (level 2) was 895±184 m (range: 520-1360 m), which was greater in wing players (975±123 m) than backcourt players (897±108 m) and pivots (827±26...

International journal of sports medicine, 2014

The present study evaluated the physical demands imposed on female elite team handball players in... more The present study evaluated the physical demands imposed on female elite team handball players in relation to playing position. Female elite team handball field players were examined during match-play over a 5-year period using video based computerized locomotion analysis of tournament matches. In addition, physiological measurements during match-play and in separate physical tests were carried out. A total distance of 4002±551 m (group means±SD) was covered per match with a total effective playing time of 50:42±5:50 min:s, while full-time players covered 4693±333 m. On average, each player (n=83) performed 663.8±99.7 activity changes per match, and the mean speed was 5.31±0.33 km · h(-1). High-intensity running constituted 0.8±0.5% of total effective playing time per match corresponding to 2.5±1.8% of the total distance covered. The amount of high-intensity running was reduced (p<0.05) 21.9% in the second half (44.9±16.8 m) compared to the first (57.5±21.3 m). Maximal oxygen upt...

International journal of sports medicine, 2013

The purpose of this study was to determine the physical demands and match-induced impairments in ... more The purpose of this study was to determine the physical demands and match-induced impairments in physical performance in male elite Team Handball (TH) players in relation to playing position. Male elite TH field players were closely observed during 6 competitive seasons. Each player (wing players: WP, pivots: PV, backcourt players: BP) was evaluated during match-play using video recording and subsequently performing locomotion match analysis. A total distance of 3 627±568 m (group means±SD) was covered per match with a total effective playing time (TPT) of 53:51±5:52 min:s, while full-time players covered 3 945±538 m. The mean speed was 6.40±1.01 km · h - 1. High-intensity running constituted only 1.7±0.9% of TPT per match corresponding to 7.9±4.9% of the total distance covered. An average of 1 482.4±312.6 activity changes per player (n=82) with 53.2±14.1 high-intensity runs were observed per match. Total distance covered was greater in BP (3 765±532 m) and WP (3 641±501 m) than PV ...

International journal of sports medicine, 2009

The present study examined the fatigue development in muscle mechanical properties with emphasis ... more The present study examined the fatigue development in muscle mechanical properties with emphasis on rapid force characteristics and neuromuscular activity in response to high level soccer match play. Young elite soccer players (n=9) were tested before (CON) and after (POST) a soccer match for maximal knee extensor and flexor isometric strength (MVC) and contractile rate of force development (RFD) with synchronous surface electromyography (EMG) recording. Furthermore, maximal vertical jump power and related parameters were assessed. Isometric knee extensor and flexor MVC decreased approximately 10% (p< or =0.01) along with a right-shift in the moment-time curve. RFD decreased approximately 9% (0-200 ms) for the knee flexors while there was a tendency towards reduced RFD during knee extension following soccer match play. Similar reductions were observed for some but not all selected EMG parameters during the MVC and RFD tests. Mechanical jump parameters generally remained unchanged...

Journal of Strength and Conditioning Research, 2015

Michalsik, LB, Madsen, K, and Aagaard, P. Technical match characteristics and influence of body a... more Michalsik, LB, Madsen, K, and Aagaard, P. Technical match characteristics and influence of body anthropometry on playing performance in male elite team handball. J Strength Cond Res 29 (2): 416-428, 2015-Modern team handball match-play imposes substantial physical and technical demands on elite players. However, only limited knowledge seems to exist about the specific working requirements in elite team handball. Thus, the purpose of this study was to examine the physical demands imposed on male elite team handball players in relation to playing position and body anthropometry. Based on continuous video recording of individual players during elite team handball match-play (62 tournament games, ;4 players per game), computerized technical match analysis was performed in male elite team handball players along with anthropometric measurements over a 6 season time span. Technical match activities were distributed in 6 major types of playing actions (shots, breakthroughs, fast breaks, tackles, technical errors, and defense errors) and further divided into various subcategories (e.g., hard or light tackles, type of shot, claspings, screenings, and blockings). Players showed 36.9 6 13.1 (group mean 6 SD) high-intense technical playing actions per match with a mean total effective playing time of 53.85 6 5.87 minutes. In offense, each player performed 6.0 6 5.2 fast breaks, received 34.5 6 21.3 tackles in total, and performed in defense 3.7 6 3.5 blockings, 3.9 6 3.0 claspings, and 5.8 6 3.6 hard tackles. Wing players (84.5 6 5.8 kg, 184.9 6 5.7 cm) were less heavy and smaller (p , 0.001) than backcourt players (94.7 6 7.1 kg, 191.9 6 5.4 cm) and pivots (99.4 6 6.2 kg, 194.8 6 3.6 cm). In conclusion, modern male elite team handball matchplay is characterized by a high number of short-term, high-intense intermittent technical playing actions. Indications of technical fatigue were observed. Physical demands differed between playing positions with wing players performing more fast breaks and less physical confrontations with opponent players than backcourt players and pivots. Body anthropometry seemed to have an important influence on playing performance because it is highly related to playing positions. The present observations suggest that male elite team handball players should implement more position-specific training regimens, while also focusing on anaerobic training and strength training.

Holloway GP, Thrush AB, Heigenhauser GJ, Tandon NN, Dyck DJ, Bonen A, Spriet LL. Skeletal muscle ... more Holloway GP, Thrush AB, Heigenhauser GJ, Tandon NN, Dyck DJ, Bonen A, Spriet LL. Skeletal muscle mitochondrial FAT/CD36 content and palmitate oxidation are not decreased in obese women. A reduction in fatty acid oxidation has been associated with lipid accumulation and insulin resistance in the skeletal muscle of obese individuals. We examined whether this decrease in fatty acid oxidation was attributable to a reduction in muscle mitochondrial content and/or a dysfunction in fatty acid oxidation within mitochondria obtained from skeletal muscle of age-matched, lean [body mass index (BMI) ϭ 23.3 Ϯ 0.7 kg/m 2 ] and obese women (BMI ϭ 37.6 Ϯ 2.2 kg/m 2 ). The mitochondrial marker enzymes citrate synthase (Ϫ34%), ␤-hydroxyacyl-CoA dehydrogenase (Ϫ17%), and cytochrome c oxidase (Ϫ32%) were reduced (P Ͻ 0.05) in obese participants, indicating that mitochondrial content was diminished. Obesity did not alter the ability of isolated mitochondria to oxidize palmitate; however, fatty acid oxidation was reduced at the whole muscle level by 28% (P Ͻ 0.05) in the obese. Mitochondrial fatty acid translocase (FAT/ CD36) did not differ in lean and obese individuals, but mitochondrial FAT/CD36 was correlated with mitochondrial fatty acid oxidation (r ϭ 0.67, P Ͻ 0.05). We conclude that the reduction in fatty acid oxidation in obese individuals is attributable to a decrease in mitochondrial content, not to an intrinsic defect in the mitochondria obtained from skeletal muscle of obese individuals. In addition, it appears that mitochondrial FAT/CD36 may be involved in regulating fatty acid oxidation in human skeletal muscle. obesity; mitochondria; fatty acid translocase/CD36; transport proteins

The Journal of Physiology, 2006

We hypothesized that suppression of endogenous testosterone blunts mRNA expression post strength ... more We hypothesized that suppression of endogenous testosterone blunts mRNA expression post strength training (ST). Twenty-two young men were randomized for treatment with the GnRH analogue goserelin (3.6 mg every 4 weeks) or placebo for a period of 12 weeks. The ST period of 8 weeks started at week 4. Strength test, blood sampling, muscle biopsies, and whole-body dual-energy X-ray absorptiometry (DXA) scan were performed at weeks 4 and 12. Muscle biopsies were taken during the final ST session (pre, post 4 h, and post 24 h). Resting serum testosterone decreased significantly (P < 0.01) in the goserelin group from 22.6 ± 1.6 (mean ± S.E.M.) to 2.0 ± 0.1 nmol l −1 (week 4), whereas it remained unchanged in the placebo group. An acute increase of serum testosterone was observed during the final ST session in the placebo group (P < 0.05), whereas a decreased response was observed in the goserelin group (P < 0.05). mRNA expression of IGF-IE(bc) and myogenin increased, while expression of myostatin decreased (P < 0.01); however, no differences were observed between the groups. Muscle strength and muscle mass showed a tendency to increase more in the placebo group than in the goserelin group (P = 0.05). In conclusion, despite blocked acute responses of testosterone and 10-to 20-fold lower resting levels in the goserelin group, ST resulted in a similar mRNA expression of myoD, myogenin, IGF-IE(abc), myostatin and androgen receptor as observed in the placebo group. Therefore, in the present study, the molecular events were the same, despite divergent muscle hypertrophy and strength gains.

Scandinavian Journal of Medicine & Science in Sports, 2007

The purpose of the present study was to determine the acute fatigue development in muscle mechani... more The purpose of the present study was to determine the acute fatigue development in muscle mechanical properties and neuromuscular activity in response to handball match play. Male elite handball players (n 5 10) were tested before and after a simulated handball match for maximal isometric strength [maximal voluntary contraction (MVC)] and rate of force development (RFD) with synchronous electromyography (EMG) recording, while maximal vertical jump parameters were assessed using force plate analysis. Quadriceps and hamstrings MVC and RFD decreased significantly post-match ( $ 10%, Po0.05 and $ 16-21%, Po0.05, respectively). During quadriceps, MVC mean EMG amplitude [mean average voltage (MAV)] decreased for the vastus lateralis (VL) and rectus femoris (RF) (21-42%, P 0.05), while MAV also decreased in the antagonist biceps femoris (BF) muscle (48-55%, Po0.01). During hamstring MVC, MAV was reduced in BF (31%, Po0.01). Maximum EMG amplitude during quadriceps MVC was reduced for the VL (28%, Po0.01) and the RF (5%, Po0.05). During hamstring MVC, maximum EMG was reduced for BF (21%, Po0.01). Post-match maximal jump height was reduced (5.2%, Po0.01), as was also work (6.8%, Po0.01), velocity of center of mass (2.4-4.0%, Po0.01) and RFD ( $ 30%, Po0.05). In conclusion, maximal (MVC) and rapid muscle force characteristics (RFD, impulse) were acutely affected concurrently with marked reductions in muscle EMG following handball match play, which may potentially lead to impaired functional performance.

Scandinavian Journal of Medicine & Science in Sports, 2007

of oxygen uptake in elite orienteers during cross-country running using telemetry. Scand J Med Sc... more of oxygen uptake in elite orienteers during cross-country running using telemetry. Scand J Med Sci Sports 1994 4: 234-238. 0 Munksgaard, 1994 Oxygen uptake (V0J was measured and economy calculated during running on a treadmill and during cross-country running in 14 male and 9 female orienteers using a telemetric system (K-2, Cosmed, Italy). The cross-country route comprised 3 parts: horizontal path running, horizontal running in light terrain and running in heavy terrain with obstacles and steep hills. Each subject accomplished the whole test route at a speed corresponding to 9625% of maximal speed and at maximal speed. The running time at maximal speed was 1923 min. The running economy was similar in treadmill and path running (21 1 2 10 vs 2102 14 ml . kg-' . km-I), but V,, per km increased in light and heavy terrain to 290+ 16 and 362t 18 ml . kg-l. km-I, respectively. There was no difference in running economy between men and women. The elite group (5 men and 3 women) demonstrated 5% better running economy than the sub-elite (9 men and 6 women) during running in light and heavy terrain, whereas no difference was seen during treadmill and path running. In conclusion, elite orienteers have better running economy in light and heavy terrain than sub-I elite orienteers. Several parameters measured during treadmill running under laboratory conditions can be used to predict performance in running competitions. Maximal oxygen uptake (VOlmax) and the fraction of V02max that can be utilized during running play important roles for the success in running competitions (1-3). Running velocity at the onset of blood lactate accumulation (VOBLA), determined from interpolation of the curve between velocity and blood lactate concentration also predicts distance running performance (4). Velocity at VO2,,, (VV02max), determined from extrapolation of the curve between running velocity and Vo2, has also been shown to predict performance in distance running (5). Furthermore, running economy, defined as the relationship between oxygen uptake and running speed, also plays an important role (6-9).

Scandinavian Journal of Medicine & Science in Sports, 2013

The effect of a whey protein- and carbohydrate (CHO)-enriched diet on the rate of muscle glycogen... more The effect of a whey protein- and carbohydrate (CHO)-enriched diet on the rate of muscle glycogen resynthesis after a soccer match was examined. Sixteen elite soccer players were randomly assigned to a group ingesting a diet rich in carbohydrates and whey protein [CHO, protein, and fat content was 71, 21, and 8E%, respectively; high content of carbohydrates and whey protein (HCP), n = 9] or a group ingesting a normal diet (55, 18, and 26E%; control [CON], n = 7) during a 48-h recovery period after a soccer match. CON and three additional players carried out a 90- and 60-min simulated match without body contacts (SIM90 and SIM60). Muscle glycogen was lowered (P &amp;amp;lt; 0.05) by 54, 48, 53, and 38% after the matches in CON, HCP, SIM90, and SIM60, respectively. Glycogen resynthesis during the first 48 h after the match was not different between CON and HCP, whereas glycogen resynthesis was slower (P &amp;amp;lt; 0.05) during the first 24 h after SIM60 than SIM90 (2.88 ± 0.84 vs 4.32 ± 0.54 mmol/kg dw/h). In HCP, glycogen content in type II muscle fibers was still lowered 48 h after the match. In conclusion, glycogen resynthesis 48 h after a soccer match is not elevated by ingestion of a HCP diet. Furthermore, glycogen resynthesis does not appear to be impaired by body contacts during a match.

Molecular and Cellular Biochemistry, 2013

Sarcoplasmic and t-tubule membrane proteins regulating sarcoplasmic Ca 2? concentration exhibit f... more Sarcoplasmic and t-tubule membrane proteins regulating sarcoplasmic Ca 2? concentration exhibit fibretype-dependent isoform expression, and play central roles in muscle contraction and relaxation. The purpose of this study was to evaluate the effects of in vitro electrical stimulation on the mRNA expression of components involved in Ca 2? regulation in oxidative and glycolytic skeletal muscle. The mRNA level of Ca 2? -ATPase (SERCA1, 2), calsequestrin (CASQ1, 2), ryanodine receptor (RyR1), and dihydropyridine receptor (Cacna1) was assessed in rat extensor digitorum longus (EDL) and soleus (SOL) muscles at 4 h of recovery following in vitro stimulations (either short intensive (SHO) 60 Hz, 5 min, or prolonged moderate (PRO) 20 Hz, 40 min). Stimulation induced acute regulation of the mRNA level of Ca 2? -regulating proteins in a manner that does not follow typical fibre-type-specific transitions. In general, stimulation decreased mRNA content of all proteins studied. Most prominent down-regulation was observed for Cacna1 (26 and 32 % after SHO and PRO, respectively, in SOL; 19 % after SHO in EDL). SERCA1, SERCA2, CASQ1, CASQ2, and RyR1 mRNA content also decreased significantly in both muscles relative to resting control. Of notice is that hexokinase II mRNA content was increased in EDL and unchanged in SOL underlining the specificity of the down-regulation of mRNA of Ca 2? regulatory proteins. The results demonstrate contraction-induced down-regulation of mRNAs for the main components of Ca 2? -regulating system in skeletal muscle. The down-regulation of both isoforms of SERCA and CASQ after a single electrical stimulation session suggests that adaptations to repeated stimulation involve further regulatory mechanisms in addition to acute mRNA responses.

Medicine & Science in Sports & Exercise, 2007

Medicine & Science in Sports & Exercise, 2002

Medicine & Science in Sports & Exercise, 1993

Medicine & Science in Sports & Exercise, 2006