Jesper L Andersen

Bispebjerg Hospital, Copenhagen University, København, Capital Region, Denmark

Are you Jesper L Andersen?

Claim your profile

Publications (58)172.04 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent studies have shown that vitamin-D intake can improve skeletal muscle function and strength in frail vitamin-D insufficient individuals. We investigated whether vitamin-D intake can improve the muscular response to resistance training in healthy young and elderly individuals, respectively. Healthy untrained young (n = 20, age 20–30) and elderly (n = 20, age 60–75) men were randomized to 16 weeks of daily supplementary intake of either 48 μg of vitamin-D + 800 mg calcium (Vitamin-D-group) or 800 mg calcium (Placebo-group) during a period and at a latitude of low sunlight (December-April, 56°N). During the last 12 weeks of the supplementation the subjects underwent progressive resistance training of the quadriceps muscle. Muscle hypertrophy, measured as changes in cross sectional area (CSA), and isometric strength of the quadriceps were determined. Muscle biopsies were analyzed for fiber type morphology changes and mRNA expression of vitamin-D receptor (VDR), cytochrome p450 27B1 (CYP27B1) and Myostatin. In the vitamin-D groups, serum 25(OH)D concentration increased significantly and at week 12 was significantly different from placebo in both young men (71.6 vs. 50.4 nmol/L, respectively) and elderly men (111.2 vs. 66.7 nmol/L, respectively). After 12 weeks of resistance training, quadriceps CSA and isometric strength increased compared to baseline in young (CSA p < 0.0001, strength p = 0.005) and elderly (CSA p = 0.001, strength p < 0.0001) with no difference between vitamin-D and placebo groups. Vitamin-D intake and resistance training increased strength/CSA in elderly compared to young (p = 0.008). In the young vitamin-D group, the change in fiber type IIa percentage was greater after 12 weeks training (p = 0.030) and Myostatin mRNA expression lower compared to the placebo group (p = 0.006). Neither resistance training nor vitamin-D intake changed VDR mRNA expression. No additive effect of vitamin-D intake during 12 weeks of resistance training could be detected on either whole muscle hypertrophy or muscle strength, but improved muscle quality in elderly and fiber type morphology in young were observed, indicating an effect of vitamin-D on skeletal muscle remodeling. Trial registration ClinicalTrials with nr. NCT01252381
    Full-text · Article · Sep 2015 · Nutrition & Metabolism
  • [Show abstract] [Hide abstract]
    ABSTRACT: Matters of fiber size and myonuclear domain; does size matter more than age? The relationship between fiber size and myonuclear content is understood poorly. Biopsy cross-sections from young and old trained and untrained healthy individuals were analyzed for fiber area and myonuclei, and 2 fiber size-dependent cluster analyses were performed. Comparing fibers of similar size, no effect of training or age was found for myonuclear domain. There was a linear relationship between fiber area and myonuclei per fiber (r=0.99; P<0.001) and a non-linear relationship between fiber area and domain (r=0.97-0.99; P<0.0001), with a markedly smaller domain in fibers <3,000 μm(2) . A larger proportion of type II fibers below 3,000 μm(2) was observed in the old. These findings suggest that age-related reductions in myonuclear domain size could be explained by a larger proportion of small fibers and highlight the usefulness of fiber size-based clusters in gaining mechanistic insight into the relationship between skeletal muscle fiber size and myonuclear content. This article is protected by copyright. All rights reserved. © 2015 Wiley Periodicals, Inc.
    No preview · Article · Apr 2015 · Muscle & Nerve
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: To determine the effect of aerobic retraining as rehabilitation after short-term leg immobilization on leg strength, leg work capacity, leg lean mass, leg muscle fibre type composition and leg capillary supply, in young and older men. Subjects and design: Seventeen young (23 ± 1 years) and 15 older (68 ± 1 [standard error of the mean; SEM] years) men had one leg immobilized for 2 weeks, followed by 6 weeks’ bicycle endurance retraining. METHODS: Maximal voluntary contraction, leg work capacity (Wmax), and leg lean mass by dual energy X-ray absorptiometry were measured at inclusion, after immobilization and after 3 and 6 weeks’ retraining. Muscle biopsies were evaluated for fibre type, fibre area, and capillarization. RESULTS: Immobilization decreased maximal voluntary contraction (–28 ± 6% and –23 ± 3%); Wmax (–13 ± 5% and –9 ± 4%) and leg lean mass (only in young, –485 ± 105g) in young and older men, respectively. Six weeks’ retraining increased maximal voluntary contraction (34 ± 8% and 17 ± 6%), Wmax (33 ± 5% and 20 ± 5%) and leg lean mass (only in young 669 ± 69 g) in young and older men, respectively, compared with the immobilized value. CONCLUSION: Short-term leg immobilization had marked effects on leg strength, and work capacity and 6 weeks’ retraining was sufficient to increase, but not completely rehabilitate, muscle strength, and to rehabilitate aerobic work capacity and leg lean mass (in the young men).
    No preview · Article · Jan 2015 · Journal of Rehabilitation Medicine
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Context: Testicular germ cell cancer (GCC) patients treated with cisplatin-etoposide-bleomycin chemotherapy (BEP) have excellent prognosis but have an increased risk of late-occurring morbidities, which may be associated with changes in the inflammatory profile. Objective: The objective of the study was to explore plasma cytokine concentrations in GCC patients randomized to resistance training or usual care during BEP, in comparison with healthy controls. Design/Setting: This was a randomized controlled trial in GCC patients enrolled from an oncology clinic, including a healthy reference group for comparison purposes. Outcome Measures: Plasma granulocyte macrophage colony-stimulating factor, interferon-γ, IL-1β, IL-2, IL-6, IL-8, IL-10, IL-12, and TNF-α were measured in fasting blood samples from GCC patients randomized to resistance training (INT; n = 15) or usual care (CON; n = 15) and healthy age-matched controls (REF; n = 19). Clinical toxicity assessments and patient-reported end points were also recorded. Results: CON and INT were balanced at baseline. Compared with REF, CON had higher concentrations of IL-10, IL-6, and interferon-γ, and INT had higher concentrations of IL-6, IL-8 and TNF-α (all P < .05). At the end of therapy, concentrations of IL-6, IL-8, and IL-10 increased in both GCC groups (all P < .01). Three months after therapy, all cytokine concentrations were comparable with the pretreatment levels in both GCC-groups but remained elevated compared with REF (P < .05). Changes in TNF-α correlated with pulmonary toxicity (P < .01). At the end of therapy, IL-6 concentrations correlated with quality of life (P < .05) and fatigue (P < .01). Conclusion: GCC patients treated with BEP display consistently elevated levels of systemic inflammatory markers compared with healthy controls. Resistance training during therapy has no impact on plasma cytokine concentrations.
    Full-text · Article · Jul 2014 · Journal of Clinical Endocrinology & Metabolism
  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract The aim was to investigate performance variables and indicators of cardiovascular health profile in elderly soccer players (SP, n = 11) compared to endurance-trained (ET, n = 8), strength-trained (ST, n = 7) and untrained (UT, n = 7) age-matched men. The 33 men aged 65-85 years underwent a testing protocol including measurements of cycle performance, maximal oxygen uptake (VO2max) and body composition, and muscle fibre types and capillarisation were determined from m. vastus lateralis biopsy. In SP, time to exhaustion was longer (16.3 ± 2.0 min; P < 0.01) than in UT (+48%) and ST (+41%), but similar to ET (+1%). Fat percentage was lower (P < 0.05) in SP (-6.5% points) than UT but not ET and ST. Heart rate reserve was higher (P < 0.05) in SP (104 ± 16 bpm) than UT (+21 bpm) and ST (+24 bpm), but similar to ET (+2 bpm), whereas VO2max was not significantly different in SP (30.2 ± 4.9 ml O2 · min(-1) · kg(-1)) compared to UT (+14%) and ST (+9%), but lower (P < 0.05) than ET (-22%). The number of capillaries per fibre was higher (P < 0.05) in SP than UT (53%) and ST (42%) but similar to ET. SP had less type IIx fibres than UT (-12% points). In conclusion, the exercise performance and cardiovascular health profile are markedly better for lifelong trained SP than for age-matched UT controls. Incremental exercise capacity and muscle aerobic capacity of SP are also superior to lifelong ST athletes and comparable to endurance athletes.
    No preview · Article · May 2014 · Journal of Sports Sciences
  • Source
    Mette Flindt Heisterberg · Jan Fahrenkrug · Jesper L Andersen

    Full-text · Article · May 2014 · Journal of Sports Sciences
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: We investigated serum testosterone and insulin-like growth factor 1 (IGF-1) levels' associations with muscle fibre size and resistance training in male dialysis patients. Methods: Male patients were included in a 16-week control period followed by 16 weeks of resistance training thrice weekly. Blood samples were obtained to analyse testosterone, luteinizing hormone (LH), IGF-1, and IGF-binding protein 3. Muscle fibres' size was analysed in biopsies from m. vastus lateralis. Results: The patients' testosterone levels were within the normal range at baseline (n = 20) (19.5 (8.2-52.1) nmol/L versus 17.6 (16.1-18.0), resp.) whereas LH levels were higher (13.0 (5.5-82.8) U/L versus 4.3 (3.3-4.6), P < 0.001, resp.). IGF-1 and IGF-binding protein 3 levels were higher in the patients compared with reference values (203 (59-590) ng/mL versus 151 (128-276), P = 0.014, and 5045 (3370-9370) ng/mL versus 3244 (3020-3983), P < 0.001, resp.). All hormone levels and muscle fibre size (n = 12) remained stable throughout the study. Age-adjusted IGF-1 was associated with type 1 and 2 fibre sizes (P < 0.05). Conclusion: Patients' total testosterone values were normal due to markedly increased LH values, which suggest a compensated primary insufficiency of the testosterone producing Leydig cell. Even though testosterone values were normal, resistance training was not associated with muscle hypertrophy. This trial is registered with ISRCTN72099857.
    Full-text · Article · Apr 2014
  • Source
    Stig Molsted · Pia Eiken · Jesper L Andersen · Inge Eidemak · Adrian P Harrison
    [Show abstract] [Hide abstract]
    ABSTRACT: Background. The aim of this study was to investigate IL-6 and 25-hydroxyvitamin D (25-OH D) associations with muscle size and muscle function in dialysis patients. Methods. Patients were included in a 16-week control period followed by 16 weeks of high-intensity resistance training thrice weekly. IL-6 and 25-OH D were analysed after an over-night fast. Muscle fibre size was analysed in biopsies from m. vastus lateralis. Muscle power was tested using a Leg Extensor Power Rig. Results. Patients (n = 36) with IL-6 ≥ 6.49 pg/ml (median) were older and had decreased muscle power and a reduced protein intake (P < 0.05) compared with patients with IL-6 < 6.49 pg/ml. IL-6 was not associated with muscle fibre size. Vitamin D deficiency (25-OH D < 50 nmol/l) was present in 51% of the patients and not associated with muscle power. IL-6 remained unchanged during the training period, whilst muscle power increased by 20-23% (P < 0.001). Conclusion. Elevated IL-6 values were associated with decreased muscle power but not with decreased muscle fibre size. Half of the patients were suffering from vitamin D deficiency, which was not associated with muscle power. IL-6 was unchanged by high-intensity resistance training in dialysis patients in this study.
    Full-text · Article · Apr 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Skeletal muscle energy metabolism has been a research focus of physiologists for more than a century. Yet, how the use of intramuscular carbohydrate and lipid energy stores are coordinated during different types of exercise remains a subject of debate. Controversy arises from contradicting data from numerous studies, which used different methodological approaches. Here we review the "pros and cons" of previously used histochemical methods and describe an optimized method to ensure the preservation and specificity of detection of both intramyocellular carbohydrate and lipid stores. For optimal preservation of muscle energy stores, air drying cryosections or cycles of freezing-thawing need to be avoided. Furthermore, optimization of the imaging settings in order to specifically image intracellular lipid droplets stained with oil red O or Bodipy-493/503 is shown. When co-staining lipid droplets with associated proteins, Bodipy-493/503 should be the dye of choice, since oil red O creates precipitates on the lipid droplets blocking the light. In order to increase the specificity of glycogen stain, an antibody against glycogen is used. The resulting method reveals the existence of two metabolically distinct myosin heavy chain I expressing fibers: I-1 fibers have a smaller crossectional area, a higher density of lipid droplets, and a tendency to lower glycogen content compared to I-2 fibers. Type I-2 fibers have similar lipid content than IIA. Exhaustive exercise lead to glycogen depletion in type IIA and IIX fibers, a reduction in lipid droplets density in both type I-1 and I-2 fibers, and a decrease in the size of lipid droplets exclusively in type I-1 fibers.
    Full-text · Article · Oct 2013 · PLoS ONE
  • Source
    Stig Molsted · Jesper L Andersen · Inge Eidemak · Adrian P Harrison
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to investigate the effects of high load resistance training on the rate of force development and neuromuscular function in patients undergoing dialysis. Twenty-nine patients were tested before and after 16 weeks of resistance training. The rate of force development was tested using the "Good Strength" dynamometer chair. Muscle strength and neuromuscular function in the m. Vastus lateralis was estimated using electromyography in a one repetition maximum test during dynamic knee extension and during a 20 second isometric knee extension with 50% of the one repetition maximum load. Muscle biopsies from the m. Vastus lateralis were analysed for morphology characteristics. One repetition maximum in knee extension increased by 46% (p<0.001) after the training programme. Rate of force development increased by 21-38% (p<0.05). The electromyography amplitude increased during 200-300 ms from 183 ± 36 μVolt to 315 ± 66 μVolt, (p<0.05), whilst electromyography frequency remained unchanged. The electromyography signals, during isometric contractions, remained unchanged. A higher rate of force development was found to be significantly associated with larger type 2 muscle fibres (r=0.647). Muscle strength in patients undergoing dialysis was increased after 16 weeks of resistance training in parallel with changed neuromuscular function and greater rate of force development, both of which have important clinical implications in terms of improved physical performance.
    Full-text · Article · Jul 2013 · Nephrology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background/aims: The aim of this controlled study was to investigate the effect of high-load strength training on glucose tolerance in patients undergoing dialysis. Methods: 23 patients treated by dialysis underwent a 16-week control period followed by 16 weeks of strength training three times a week. Muscle fiber size, composition and capillary density were analyzed in biopsies obtained in the vastus lateralis muscle. Glucose tolerance and the insulin response were measured by a 2-hour oral glucose tolerance test. Results: All outcome measures remained unchanged during the control period. After strength training the relative area of type 2X fibers was decreased. Muscle fiber size and capillary density remained unchanged. After the strength training, insulin concentrations were significantly lower in patients with impaired glucose tolerance or type 2 diabetes (n = 14) (fasting insulin from 68 ± 12 (46-96) to 54 ± 10 (37-77) pmol/l, p < 0.05, 2-hour insulin from 533 ± 104 (356-776) to 344 ± 68 (226-510) pmol/l, p < 0.05, total insulin area under the curve from 1,868 ± 334 (1,268-2,536) to 1,465 ± 222 (1,094-1,913), p < 0.05). Insulin concentrations were unchanged in patients with normal glucose tolerance (n = 9). Conclusion: The conducted strength training was associated with a significant improvement in glucose tolerance in patients with impaired glucose tolerance or type 2 diabetes undergoing dialysis. The effect was apparently not associated with muscle hypertrophy, whereas the muscle fiber type composition was changed.
    Full-text · Article · Jul 2013 · Nephron Clinical Practice
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recovery of skeletal muscle mass from immobilisation-induced atrophy is faster in young than older individuals, yet the cellular mechanisms remain unknown. We examined the cellular and molecular regulation of muscle recovery in young and old human subjects subsequent to 2 weeks of immobility-induced muscle atrophy. Re-training consisted of 4 weeks of supervised resistive exercise in 9 older (OM: 67.3yrs, range 61-74) and 11 young (YM: 24.4yrs, range 21-30) males. Measures of myofiber area (MFA), Pax7-positive satellite cells (SC) associated with type I and type II muscle fibres, as well as gene expression analysis of key growth and transcription factors associated with local skeletal muscle milieu were performed after 2 weeks immobility (Imm) and following 3 days (+3d) and 4 weeks (+4wks) of re-training. OM demonstrated no detectable gains in MFA (VL muscle) and no increases in number of Pax7-positive SCs following 4 wks re-training, whereas YM increased their MFA (p<0.05), number of Pax7-positive cells, and had more Pax7-positive cells per type II fibre than OM at +3d and +4wks (p<0.05). No age-related differences were observed in mRNA expression of IGF-1Ea, MGF, MyoD1 and HGF with re-training, whereas myostatin expression levels were more down-regulated in YM compared to OM at +3d (p<0.05). In conclusion, the diminished muscle re-growth after immobilisation in elderly humans was associated with lesser response in satellite cell proliferation in combination with an age-specific regulation of myostatin. In contrast, expression of local growth factors did not seem to explain the age related difference in muscle mass recovery.
    No preview · Article · Jun 2013 · The Journal of Physiology
  • Source
    Dataset: Figure S2
    Charlotte Suetta · Ulrik Frandsen · Line Jensen · Mette Munk Jensen · Jakob G. Jespersen · Lars G. Hvid · Monika Bayer · Stine J. Petersson · Henrik D. Schrøder · Jesper L. Andersen · Katja M. Heinemeier · Per Aagaard · Peter Schjerling · Michael Kjaer
    [Show abstract] [Hide abstract]
    ABSTRACT: Changes in the transcriptional status of NF-κB, TNF-α and IL-6 as a result of immobility induced disuse muscle atrophy. The mRNA level of NF-κB, TNF-α and IL-6 was determined using qRT-PCR. A–B. A part from a small increase in the expression of NF-κB at 14 d, we did not find any change in the mRNA expression of NF-κB or TNF-α at any time-point in neither young nor old muscle. C. A part from a small increase in the expression level of IL-6 mRNA in both young and aged muscle after 4 days of immobility, no major induction of this pro-inflammatory cytokine was observed. * Time effect, p<0.05 compared to pre. * Time effect, p<0.05 bar indicates young and old combined compared to pre. Data are geometric means ± back-transformed SEM. (TIF)
    Preview · Dataset · Dec 2012
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Important insights concerning the molecular basis of skeletal muscle disuse-atrophy and aging related muscle loss have been obtained in cell culture and animal models, but these regulatory signaling pathways have not previously been studied in aging human muscle. In the present study, muscle atrophy was induced by immobilization in healthy old and young individuals to study the time-course and transcriptional factors underlying human skeletal muscle atrophy. The results reveal that irrespectively of age, mRNA expression levels of MuRF-1 and Atrogin-1 increased in the very initial phase (2-4 days) of human disuse-muscle atrophy along with a marked reduction in PGC-1α and PGC-1β (1-4 days) and a ∼10% decrease in myofiber size (4 days). Further, an age-specific decrease in Akt and S6 phosphorylation was observed in young muscle within the first days (1-4 days) of immobilization. In contrast, Akt phosphorylation was unchanged in old muscle after 2 days and increased after 4 days of immobilization. Further, an age-specific down-regulation of MuRF-1 and Atrogin-1 expression levels was observed following 2 weeks of immobilization, along with a slowing atrophy response in aged skeletal muscle. Neither the immediate loss of muscle mass, nor the subsequent age-differentiated signaling responses could be explained by changes in inflammatory mediators, apoptosis markers or autophagy indicators. Collectively, these findings indicate that the time-course and regulation of human skeletal muscle atrophy is age dependent, leading to an attenuated loss in aging skeletal muscle when exposed to longer periods of immobility-induced disuse.
    Full-text · Article · Dec 2012 · PLoS ONE
  • Source
    Stig Molsted · Adrian P Harrison · Inge Eidemak · Jesper L Andersen
    [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE: The aim of this study was to investigate the effects of high-load strength training and protein intake in patients undergoing dialysis with a focus on muscle strength, physical performance, and muscle morphology. DESIGN: This was a randomized controlled study conducted in three dialysis centers. SUBJECTS: Subjects for the study included 29 patients undergoing dialysis. INTERVENTION: The participants went through a control period of 16 weeks before completing 16 weeks of strength training. Before the training period, the participants were randomly assigned to receive a protein or a nonprotein drink after every training session. MAIN OUTCOME MEASURE: Muscle strength and power were tested using the good strength equipment and the leg extensor power rig. Physical performance and function were assessed using a chair stand test and the Short Form 36 questionnaire. Muscle fiber type size and composition were analyzed in biopsies obtained from the m. vastus lateralis. RESULTS: All variables remained unchanged during the control period. After training, muscle strength and power, physical performance, and physical function increased significantly. Muscle fiber composition was changed by a relative decrease in type 2x muscle fiber number whereas muscle size at the fiber level was unchanged. There were no effects of combining the training with protein intake. CONCLUSIONS: High-load strength training is associated with improvements in muscle strength and power, physical performance, and quality of life. The effects were surprisingly not associated with muscle hypertrophy, and the results did not reveal any additional benefit of combining the training with protein intake. The positive results in muscle strength and physical performance have clinically relevant implications in the treatment of patients undergoing dialysis.
    Full-text · Article · Sep 2012 · Journal of Renal Nutrition
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Effects of resistance training and detraining on glucose and insulin responses to an oral glucose load, muscle fiber type, and muscular performance in the offspring of those with type 2 diabetes (familial insulin resistant (FIR)) were investigated. Methods: Six FIR participants and 10 controls (C) completed 9 wk of resistance training and 9 wk of detraining. Measures of strength and power, an oral glucose tolerance test, and a muscle biopsy to determine myosin heavy chain (MHC) fiber composition were taken at baseline (T1), after training (T2), and after detraining (T3). Results: Three-repetition maximum increased (P ≤ 0.001) similarly in both groups in all strength measures, e.g., leg press (FIR T1, T2: 121 ± 34 kg, 186 ± 50 kg; C T1, T2: 137 ± 42 kg, 206 ± 64 kg, respectively (means ± SD)). Wingate peak power increased (FIR T1, T2: 505 ± 137 W, 523 ± 143 W; C T1, T2: 636 ± 211 W, 672 ± 223 W, respectively; P ≤ 0.005 (means ± SD)). Training reduced insulin area under the curve more (P = 0.050) in FIR (T1, T2: 1219 ± 734 pmol·L, 837 ± 284 pmol·L, respectively (means ± SD)) than that in C (T1, T2: 647 ± 268 pmol·L, 635 ± 258 pmol·L, respectively (means ± SD)). MHC distribution did not change with training. Strength (three-repetition maximum measures) decreased with detraining (P ≤ 0.001) although Wingate power did not. Detraining increased insulin area under the curve (P = 0.018) in FIR (T2, T3: 837 ± 285 pmol·L, 1040 ± 194 pmol·L, respectively (means ± SD)) but not in C (T2, T3: 635 ± 258 pmol·L, 625 ± 213 pmol·L, respectively (means ± SD)). MHC IIX fibers increased with detraining (P = 0.026). Conclusion: FIR appears to have exaggerated responses to resistance training and detraining, with a greater reduction in insulin release with glucose ingestion after training and increase when training ceases. Resistance training has a significant effect on insulin responses and may reduce future risk of type 2 diabetes mellitus among FIR.
    No preview · Article · Jul 2012 · Medicine and science in sports and exercise
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to make a comprehensive gathering of consecutive detailed blood samples from professional soccer players, and to analyze different blood parameters in relation to seasonal changes in training and match exposure.Blood samples were collected five times during a six months period and analyzed for 37 variables in 27 professional soccer players from the best Danish league. Additionally, players were tested for body composition, VO2max and physical performance by the Yo-Yo intermittent endurance sub-max test (IE2).Multiple variations in blood parameters occurred during the observation period, including a decrease in hemoglobin and an increase in hematocrit as the competitive season progressed. Iron and transferrin was stabile, whereas ferritin showed a decrease at the end of the season. IgA and IgM increased in the period with basal physical training and at the end of the season. Leucocytes decreased with increased physical training. Lymphocytes decreased at the end of the season. VO2max decreased towards the end of the season whereas no significant changes were observed in the IE2 test.The regular blood samples from elite soccer players reveal significant changes that may be related to changes in training pattern, match exposure or length of the match-season. Especially the end of the preparation-season and at the end of the competitive season seem to be time points were the blood-derived values indicate that the players are under excessive physical strain and might be more subjected to a possible overreaching/overtraining conditions.We suggest that regular analyzes of blood samples could be an important initiative to optimize training adaptation, training load and game participation, but sampling has to be regular and a database has to be build for each individual player.
    Full-text · Article · Jun 2012 · The Journal of Strength and Conditioning Research
  • [Show abstract] [Hide abstract]
    ABSTRACT: Hemiparesis-disability and muscle weakness of 1 side of the body-is a common consequence of stroke. High-intensity strength training may be beneficial to regain function, but strength coaches in the field of rehabilitation need evidence-based guidelines. The purpose of this study was to evaluate the effect of intensive physical rehabilitation on neuromuscular and functional adaptations in outpatients suffering from hemiparesis after stroke. A within-subject repeated-measures design with the paretic leg as the experimental leg and the nonparetic leg as the control leg was used. Eleven outpatients with hemiparesis after stroke participated in 12 weeks of intensive physical rehabilitation comprising unilateral high-intensity strength training with near-maximal loads (4-12 repetition maximum) and body weight supported treadmill training. At baseline and 12-week follow-up, the patients went through testing consisting of isokinetic muscle strength, neuromuscular activation measured with electromyography (EMG), electrically evoked muscle twitch contractile properties, and gait performance (10-m Walk Test and 6-min Walk Test). After the 12-week conditioning program, knee extensor and flexor strength increased during all contraction modes and velocities in the paretic leg. Significant increases were observed for agonist EMG amplitude at slow concentric and slow eccentric contraction. Twitch torque increased, whereas twitch time-to-peak tension remained unchanged. By contrast, no significant changes were observed in the nonparetic control leg. Gait performance increased 52-68%. In conclusion, intensive physical rehabilitation after stroke leads to clinically relevant neuromuscular improvements, leading to increased voluntary strength during a wide range of contraction modes and velocities, and improved gait velocity. Strength training coaches working in the field of rehabilitation can use this knowledge to safely and efficiently add high-intensity strength training to existing rehabilitation paradigms.
    No preview · Article · Sep 2011 · The Journal of Strength and Conditioning Research
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Standard treatment for patients with disseminated germ cell tumors is combination chemotherapy with bleomycin, etoposide and cisplatin (BEP). This treatment is highly effective, but the majority of patients experience severe adverse effects during treatment and are at risk of developing considerable long-term morbidity, including second malignant neoplasms, cardiovascular disease, and pulmonary toxicity. One neglected side effect is the significant muscular fatigue mentioned by many patients with testicular cancer both during and after treatment. Very limited information exists concerning the patho-physiological effects of antineoplastic agents on skeletal muscle. The primary aim of this study is to investigate the effects of BEP-treatment on the skeletal musculature in testicular cancer patients, and to examine whether the expected treatment-induced muscular deterioration can be attenuated or even reversed by high intensity progressive resistance training (HIPRT). The PROTRACT study is a randomized controlled trial in 30 testicular cancer patients undergoing three cycles of BEP chemotherapy. Participants will be randomized to either a 9-week HIPRT program (STR) initiated at the onset of treatment, or to standard care (UNT). 15 healthy matched control subjects (CON) will complete the same HIPRT program. All participants will take part in 3 assessment rounds (baseline, 9 wks, 21 wks) including muscle biopsies, maximum muscle strength tests, whole body DXA scan and blood samples. Primary outcome: mean fiber area and fiber type composition measured by histochemical analyses, satellite cells and levels of protein and mRNA expression of intracellular mediators of protein turnover. Secondary outcomes: maximum muscle strength and muscle power measured by maximum voluntary contraction and leg-extensor-power tests, body composition assessed by DXA scan, and systemic inflammation analyzed by circulating inflammatory markers, lipid and glucose metabolism in blood samples. Health related Quality of Life (QoL) will be assessed by validated questionnaires (EORTC QLQ-C30, SF-36). This study investigates the muscular effects of antineoplastic agents in testicular cancer patients, and furthermore evaluates whether HIPRT has a positive influence on side effects related to chemotherapy. A more extensive knowledge of the interaction between cytotoxic-induced physiological impairment and exercise-induced improvement is imperative for the future development of optimal rehabilitation programs for cancer patients. Current Controlled Trials ISRCTN32132990.
    Full-text · Article · Aug 2011 · BMC Cancer
  • [Show abstract] [Hide abstract]
    ABSTRACT: Very little attention has been given to the combined effects of aging and disuse as separate factors causing deterioration in muscle mechanical function. Thus the purpose of this study was to investigate the effects of 2 wk of immobilization followed by 4 wk of retraining on knee extensor muscle mechanical function (e.g., maximal strength and rapid force capacity) and muscle fiber morphology in 9 old (OM: 67.3 ± 1.3 yr) and 11 young healthy men (YM: 24.4 ± 0.5 yr) with comparable levels of physical activity. Following immobilization, OM demonstrated markedly larger decreases in rapid force capacity (i.e., rate of force development, impulse) than YM (∼ 20-37 vs. ∼ 13-16%; P < 0.05). In contrast, muscle fiber area decreased in YM for type I, IIA, and IIx fibers (∼ 15-30%; P < 0.05), whereas only type IIa area decreased in OM (13.2%; P < 0.05). Subsequent retraining fully restored muscle mechanical function and muscle fiber area in YM, whereas OM showed an attenuated recovery in muscle fiber area and rapid force capacity (tendency). Changes in maximal isometric and dynamic muscle strength were similar between OM and YM. In conclusion, the present data reveal that OM may be more susceptible to the deleterious effects of short-term muscle disuse on muscle fiber size and rapid force capacity than YM. Furthermore, OM seems to require longer time to recover and regain rapid muscle force capacity, which may lead to a larger risk of falling in aged individuals after periods of short-term disuse.
    No preview · Article · Dec 2010 · Journal of Applied Physiology

Publication Stats

3k Citations
172.04 Total Impact Points

Institutions

  • 2008-2015
    • Bispebjerg Hospital, Copenhagen University
      • Institute for Sports Medicine
      København, Capital Region, Denmark
  • 1999-2015
    • IT University of Copenhagen
      København, Capital Region, Denmark
  • 2003-2007
    • Copenhagen University Hospital
      København, Capital Region, Denmark
  • 2006
    • Wernersville State Hospital
      Wernersville, Pennsylvania, United States
  • 2002
    • UCL Eastman Dental Institute
      Londinium, England, United Kingdom