A de Haan

Manchester Metropolitan University, Manchester, England, United Kingdom

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Publications (207)570.97 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: Abstract Purpose: This study investigates the effectiveness of Lokomat + conventional therapy in recovering walking ability in non-ambulatory subacute stroke subjects involved in inpatient rehabilitation. Method: Thirty first-ever stroke patients completed 8 weeks of intervention. One group (n = 16) received Lokomat therapy twice a week, combined with three times 30 min a week of conventional overground therapy. The second group (n = 14) received conventional assisted overground therapy only, during a similar amount of time (3.5 h a week). The intervention was part of the normal rehabilitation program. Primary outcome measure was walking speed. Secondary outcome measures assessed other walking- and mobility-related tests, lower-limb strength and quality of life measures. All outcome measures were assessed before and after the intervention and at wk 24 and wk 36 after start of the intervention. Results: Patients showed significant (p < 0.05) gains in walking speed, other walking- and mobility related tests, and strength of the paretic knee extensors relative to baseline at all assessments. However, there were no significant differences in improvements in any of the variables between groups at any time during the study. Conclusion: These results indicate that substituting Lokomat therapy for some of conventional therapy is as effective in recovering walking ability in non-ambulatory stroke patients as conventional therapy alone. Implications for Rehabilitation Recovery of walking after stroke is important. Robot-assisted therapy is currently receiving much attention in research and rehabilitation practice as devices such as the Lokomat seem to be promising assistive devices. Technical developments, sub-optimal study designs in literature and new therapy insights warrant new effectiveness studies. Results of a financially and practically feasible study indicate that substituting Lokomat therapy for some of conventional therapy is as effective in recovering walking ability in non-ambulatory stroke patients as compared to conventional overground therapy alone.
    Disability and rehabilitation. Assistive technology 03/2014;
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    ABSTRACT: The aim of this study was to investigate which parameters of physical functioning are associated with bone quality and fracture risk and whether gender-specific differences exist within these associations. We studied 1,486 participants of the Longitudinal Aging Study Amsterdam. As measures of physical functioning, handgrip strength, physical performance, and level of physical activity were assessed. To assess bone quality, broadband ultrasound attenuation (BUA) and speed of sound (SOS) were measured at baseline using quantitative ultrasound and bone mineral density (BMD) at baseline and after 3 years by dual-energy X-ray absorptiometry. In addition, fracture incidence over 6 years was assessed. After adjustment for confounders (age, serum 25[OH]D, smoking, and body weight), in men, physical performance was positively related to BUA, SOS, and BMD cross-sectionally and to BMD longitudinally. Using Cox proportional hazards model, in men higher handgrip strength and physical performance were associated with reduced fracture risk after adjustment for confounders (hazard ratio [HR] 0.96, 95 % confidence interval [CI] 0.92-0.99, and HR 0.89, 95 % CI 0.80-0.98, respectively). In women, a moderate level of physical activity was related to reduced fracture risk (HR 0.57, 95 % CI 0.33-0.99). In conclusion, in men, higher handgrip strength and physical performance are related to higher bone quality and reduced fracture risk, whereas in women, a moderate to high level of physical activity is associated with reduced fracture risk. These measurements may contribute to the identification of individuals at high fracture risk. Both the causality of and explanations for gender-specific differences in these relationships remain subject to further studies.
    Calcified Tissue International 01/2014; · 2.50 Impact Factor
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    ABSTRACT: Human aging is associated with a progressive decline in skeletal muscle mass and force generating capacity, however the exact mechanisms underlying these changes are not fully understood. Rodents models have often been used to enhance our understanding of mechanisms of age-related changes in human skeletal muscle. However, to what extent age-related alterations in determinants of muscle force generating capacity observed in rodents resemble those in humans has not been considered thoroughly. This review compares the effect of aging on muscle force generating determinants (muscle mass, fiber size, fiber number, fiber type distribution and muscle specific tension), in men and male rodents at similar relative age. It appears that muscle aging in male F344*BN rat resembles that in men most; 32–35-month-old rats exhibit similar signs of muscle weakness to those of 70–80-yr-old men, and the decline in 36–38-month-old rats is similar to that in men aged over 80 yrs. For male C57BL/6 mice, age-related decline in muscle force generating capacity seems to occur only at higher relative age than in men. We conclude that the effects on determinants of muscle force differ between species as well as within species, but qualitatively show the same pattern as that observed in men.
    Ageing research reviews 01/2014; 14:43-55. · 5.62 Impact Factor
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    ABSTRACT: Objective. To investigate the feasibility and effects of additional preoperative high intensity strength training for patients awaiting total knee arthroplasty (TKA). Design. Clinical controlled trial. Patients. Twenty-two patients awaiting TKA. Methods. Patients were allocated to a standard training group or a group receiving standard training with additional progressive strength training for 6 weeks. Isometric knee extensor strength, voluntary activation, chair stand, 6-minute walk test (6MWT), and stair climbing were assessed before and after 6 weeks of training and 6 and 12 weeks after TKA. Results. For 3 of the 11 patients in the intensive strength group, training load had to be adjusted because of pain. For both groups combined, improvements in chair stand and 6MWT were observed before surgery, but intensive strength training was not more effective than standard training. Voluntary activation did not change before and after surgery, and postoperative recovery was not different between groups (P > 0.05). Knee extensor strength of the affected leg before surgery was significantly associated with 6-minute walk (r = 0.50) and the stair climb (r - = 0.58, P < 0.05). Conclusion. Intensive strength training was feasible for the majority of patients, but there were no indications that it is more effective than standard training to increase preoperative physical performance. This trial was registered with NTR2278.
    Rehabilitation research and practice. 01/2014; 2014:462750.
  • Neuromuscular Disorders 11/2013; · 3.46 Impact Factor
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    ABSTRACT: Osteoarthritis (OA) of the knee or hip is associated with limitations in activities of daily life. There are only a few long-term studies on how knee or hip OA affects the course of physical performance. The aim of this study was to investigate the effects of knee or hip OA on physical performance during a follow-up period of 10 years. Participants in the Longitudinal Aging Study Amsterdam with self-reported hip or knee OA (N = 155) were prospectively followed for 10 years on 4 occasions from the onset of OA and compared to participants without OA (N = 1004). Physical performance was tested with walk, chair stand and balance tests. Scores for each test were summed to a total performance score (range 0-12), higher scores indicating better performance. Generalized estimating equations were used to analyze differences between participants with and without OA, unadjusted as well as adjusted for confounders. There was a significant interaction between OA and sex (P = 0.068). Both in men and women, total performance was lower for participants with OA, with greater differences in men. Chair stand and walking performance (P < 0.05), but not balance, were lower in participants with OA. After adjustment for confounders, these associations remained significant in men but not in women. Additional analyses correcting for follow-up duration and attrition showed lower performance scores for men and women with OA. OA negatively affected physical performance 3-6 years after it was first reported. Performance in men with OA was more affected than in women.
    Aging - Clinical and Experimental Research 08/2013; · 1.01 Impact Factor
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    ABSTRACT: To develop an undemanding test for endurance capacity of the knee extensor muscles, which can also be applied with frail participants. We hypothesized firstly that the first objective indications for peripheral fatigue during incremental unilateral repetitive isometric knee extensor contractions could be used to assess a fatigue threshold (FT), secondly, that torque at FT would depend on training status and thirdly, that this torque could easily be sustained for 30 min. Five trained and five untrained participants performed 5-min-bouts of 60 repetitive contractions (3s on, 2s off). Torque, set at 25%MVC was increased by 5%MVC in subsequent bouts. The highest torque for which rsEMG remained stable during the bout was defined FT. On separate occasions, 30 min bouts were performed at and above FT to assess sustainable torque. Changes in gas exchange parameters, heart rate and ratings of perceived exertion (RPE) were monitored to corroborate fatigue threshold. At FT (RPE: 5.7±1.7) torque was higher (p<0.05) in trained (41.4±5.8 %MVC) than untrained participants (30.5±1.8 %MVC). Sustainable torque was ∼4% higher than (p<0.05) and significantly related to FT (r=0.79).When torque was increased by 5%MVC, significant increases in rsEMG and VO2 were found. During incremental knee extensor contractions, FT could be assessed at sub maximal exercise intensity. FT was higher in trained than untrained participants and related to exercise sustainability. With the use of FT, changes in endurance capacity of single muscle groups can potentially also be determined in frail participants for whom exercise performed till exhaustion is unwarranted.
    Medicine and science in sports and exercise 07/2013; · 3.71 Impact Factor
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    ABSTRACT: The present study investigated whether intrinsic fatigability of the muscle fibers is reduced in patients with post-polio syndrome (PPS). This may contribute to the muscle fatigue complaints reported by patients with PPS. For this purpose, we assessed contractile properties and fatigue resistance of the knee extensor muscles using repeated isometric electrically evoked contractions in 38 patients with PPS and 19 age-matched healthy subjects. To determine whether any difference in fatigue resistance between both groups could be attributed to differences in aerobic capacity of the muscle fibers, 9 patients with PPS and 11 healthy subjects performed the same protocol under arterial occlusion. Results showed that fatigue resistance of patients with PPS was comparable to that in controls, both in the situation with intact circulation and with occluded blood flow. Together, our findings suggest that there are no differences in contractile properties and aerobic muscle capacity that may account for the increased muscle fatigue perceived in PPS.
    Neuromuscular Disorders 07/2013; · 3.46 Impact Factor
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    ABSTRACT: Purpose: The best way to apply precooling for endurance exercise in the heat is still unclear. The authors analyzed the effect of different preparation regimens on pacing during a 15-km cycling time trial in the heat. Methods: Ten male subjects completed four 15-km time trials (30°C), preceded by different preparation regimes: 10 min cycling (WARM-UP), 30 min scalp cooling of which 10 min was cycling (SC+WARM-UP), ice-slurry ingestion (ICE), and ice slurry ingestion + 30 min scalp cooling (SC+ICE). Results: No differences were observed in finish time and mean power output, although power output was lower for WARM-UP than for SC+ICE during km 13-14 (17 ± 16 and 19 ± 14 W, respectively) and for ICE during km 13 (16 ± 16 W). Rectal temperature at the start of the time trial was lower for both ICE conditions (~36.7°C) than both WARM-UP conditions (~37.1°C) and remained lower during the first part of the trial. Skin temperature and thermal sensation were lower at the start for SC+ICE. Conclusions: The preparation regimen providing the lowest body-heat content and sensation of coolness at the start (SC+ICE) was most beneficial for pacing during the latter stages of the time trial, although overall performance did not differ.
    International journal of sports physiology and performance 05/2013; 8(3):307-11. · 2.25 Impact Factor
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    ABSTRACT: Abstract We hypothesised that experienced runners would select a stride frequency closer to the optimum (minimal energy costs) than would novice runners. In addition, we expected that optimal stride frequency could simply be determined by monitoring heart rate without measuring oxygen consumption ([Formula: see text]O2). Ten healthy males (mean±s: 24±2 year) with no running training experience and 10 trained runners of similar age ran at constant treadmill speed corresponding to 80% of individual ventilatory threshold. For two days, they ran at seven different stride frequencies (self-selected stride frequency±18%) imposed by a metronome. Optimal stride frequency was based on the minimum of a second-order polynomial equation fitted through steady state [Formula: see text]O2 at each stride frequency. Running cost (mean±s) at optimal stride frequency was higher (P < 0.05) in novice (236±31 ml O2·kg(-1.)km(-1)) than trained (189±13 ml O2·kg(-1.)km(-1)) runners. Self-selected stride frequency (mean±s; strides(.)min(-1)) for novice (77.8±2.8) and trained runners (84.4±5.3) were lower (P < 0.05) than optimal stride frequency (respectively, 84.9±5.0 and 87.1±4.8). The difference between self-selected and optimal stride frequency was smaller (P < 0.05) for trained runners. In both the groups optimal stride frequency established with heart rate was not different (P > 0.3) from optimal stride frequency based on [Formula: see text]O2. In each group and despite limited variation between participants, optimal stride frequencies derived from [Formula: see text]O2 and heart rate were related (r > 0.7; P < 0.05). In conclusion, trained runners chose a stride frequency closer to the optimum for energy expenditure than novices. Heart rate could be used to establish optimal stride frequency.
    European journal of sport science : EJSS : official journal of the European College of Sport Science. 04/2013;
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    ABSTRACT: Purpose: Training for improvement of oxidative capacity of muscle fibers may be attenuated when concurrently training for peak power. However, due to fiber type specific recruitment such attenuation may only account for high oxidative muscle fibers. Here we investigate the effects of concurrent training on oxidative capacity (as measured by succinate dehydrogenase (SDH) activity) by using task specific recruitment of the high and low oxidative compartment of rat medial gastrocnemius muscle (GM). Methods: 40 rats were subjected to either 6 weeks of peak power (PT, n=10), endurance (ET, n=10), concurrent peak power and endurance training (PET, n=10) or no-training (control, n=10). SDH activity, mRNA expression of SDH, peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α), receptor-interacting protein 140 (RIP140) and BCL2/adenovirus E1B 19 kd-interacting protein 3 (BNIP3) as well as PGC-1αprotein levels were analyzed in the low and high oxidative region of the GM. Results: In the low oxidative compartment, PT and PET induced a 30% decrease in SDH activity of type IIB fibers compared to controls and ET (p<0.001) without changes in mRNA or protein levels. In the high oxidative compartment, after ET, SDH mRNA levels were 42% higher and RIP14 mRNA levels 33% lower compared to controls, which did not result in changes in SDH activity. Conclusion: These results indicate that in compartmentalized rat GM, peak power on top of endurance training attenuated transcription of mRNA for mitochondrial proteins in high oxidative muscle fibers. In low oxidative type IIB fibers, peak power training substantially decreased SDH activity, which was not related to lower SDH mRNA levels. It is concluded that PT and PET enhanced mitochondrial degradation in the low oxidative compartment of rat GM.
    Medicine and science in sports and exercise 03/2013; · 3.71 Impact Factor
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    ABSTRACT: OBJECTIVE: To determine the relative aerobic load, walking speed and walking economy of older adults with a lower limb prosthesis, and to predict the effect of an increased aerobic capacity on their walking ability. DESIGN: Cross-sectional. SETTING: Human motion laboratory at a rehabilitation center. PARTICIPANTS: A convenience sample of 36 older adults who underwent lower limb amputation due to vascular deficiency or trauma and 21 able bodied controls. INTERVENTIONS: not applicable. MAIN OUTCOME MEASURES: Peak aerobic capacity and the oxygen consumption while walking were determined. The relative aerobic load and walking economy were assessed as a function of walking speed, and a data-based model was constructed to predict the effect of an increased aerobic capacity on walking ability. RESULTS: People with a vascular amputation walk at a substantial higher (45.2%) relative aerobic load than people with an amputation due to trauma. The preferred walking speed in both groups of amputees was slower than that of able bodied controls and below their most economical walking speed. We predicted that a 10% increase in peak aerobic capacity could potentially result in a reduction in the relative aerobic load of 9.1%, an increase in walking speed of 17.3% and 13.9%, and an improvement in the walking economy of 6.8% and 2.9%, for people after a vascular or traumatic amputation, respectively. CONCLUSION: Current findings corroborate the notion that, especially in people with a vascular amputation, the peak aerobic capacity is an important determinant for walking ability. The data provides quantitative predictions on the effect of aerobic training; however, future research is needed to experimentally confirm these predictions.
    Archives of physical medicine and rehabilitation 03/2013; · 2.18 Impact Factor
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    ABSTRACT: Physiological and perceptual effects of wind cooling are often intertwined and have scarcely been studied in self-paced exercise. Therefore, we aimed to investigate (1) the independent perceptual effect of wind cooling and its impact on performance and (2) the responses to temporary wind cooling during self-paced exercise. Ten male subjects completed four trials involving 15 min standardized incremental intensity cycling, followed by a 15-km self-paced cycling time trial. Three trials were performed in different climates inducing equivalent thermal strain: hot humid with wind (WIND) and warm humid (HUMID) and hot dry (DRY) without wind. The fourth trial (W3-12) was equal to HUMID, except that wind cooling was unexpectedly provided during kilometers 3-12. Physiological, perceptual and performance parameters were measured. Subjects felt generally cooler during the WIND than the HUMID and DRY trials, despite similar heart rate, rectal and skin temperatures and a WBGT of ~4 °C higher. The cooler thermal sensation was not reflected in differences in thermal comfort or performance. Comparing W3-12 to HUMID, skin temperature was 1.47 ± 0.43 °C lower during the wind interval, leading to more favorable ratings of perceived exertion, thermal sensation and thermal comfort. Overall, power output was higher in the W3-12 than the HUMID-trial (256 ± 29 vs. 246 ± 22 W), leading to a 67 ± 48 s faster finish time. In conclusion, during self-paced exercise in the heat, wind provides immediate and constant benefits in physiological strain, thermal perception and performance. Independent of physiological changes, wind still provides a greater sensation of coolness, but does not impact thermal comfort or performance.
    Arbeitsphysiologie 02/2013; · 2.66 Impact Factor
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    ABSTRACT: Improvement of muscle peak power and oxidative capacity are generally presumed to be mutually exclusive. However, this may not be valid by using fibre type-specific recruitment. Since rat medial gastrocnemius muscle (GM) is composed of high and low oxidative compartments which are recruited task specifically, we hypothesised that the adaptive responses to peak power training were unaffected by additional endurance training. Thirty rats were subjected to either no training (control), peak power training (PT), or both peak power and endurance training (PET), which was performed on a treadmill 5 days per week for 6 weeks. Maximal running velocity increased 13.5% throughout the training and was similar in both training groups. Only after PT, GM maximal force was 10% higher than that of the control group. In the low oxidative compartment, mRNA levels of myostatin and MuRF-1 were higher after PT as compared to those of control and PET groups, respectively. Phospho-S6 ribosomal protein levels remained unchanged, suggesting that the elevated myostatin levels after PT did not inhibit mTOR signalling. In conclusion, even by using task-specific recruitment of the compartmentalized rat GM, additional endurance training interfered with the adaptive response of peak power training and attenuated the increase in maximal force after power training.
    BioMed research international. 01/2013; 2013:935671.
  • Neuromuscular Disorders 01/2013; · 3.46 Impact Factor
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    ABSTRACT: It has been suggested that aerobic training should be considered in stroke rehabilitation programs to counteract detrimental health effects and decrease cardiovascular risk caused by inactivity. Robot-assisted treadmill exercise (using a Lokomat device) has the potential to increase the duration of walking therapy relative to conventional overground therapy. We investigated whether exercise intensity during Lokomat therapy is adequate to elicit a training effect and how assistance during walking in the Lokomat affects this exercise intensity. Ten patients with stroke (age 54 +/- 9 yr) walked in both the Lokomat and in a hallway. Furthermore, 10 nondisabled subjects (age 43 +/- 14 yr) walked in the Lokomat at various settings and on a treadmill at various speeds. During walking, oxygen consumption and heart rate were monitored. Results showed that for patients with stroke, exercise intensity did not reach recommended levels (30% heart rate reserve) for aerobic training during Lokomat walking. Furthermore, exercise intensity during walking in the Lokomat (9.3 +/- 1.6 mL/min/kg) was lower than during overground walking (10.4 +/- 1.3 mL/min/kg). Also, different settings of the Lokomat only had small effects on exercise intensity in nondisabled subjects.
    The Journal of Rehabilitation Research and Development 12/2012; 49(10):1537-46. · 1.78 Impact Factor
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    ABSTRACT: Physical inactivity and exercise training result in opposite adaptations of vascular structure. However, the molecular mechanisms behind these adaptations are not completely understood. Therefore, we used a unique study design to examine both vascular characteristics of the superficial femoral artery (using ultrasound) and gene expression levels (from a muscle biopsy) in human models for physical deconditioning and exercise training. First, we compared able-bodied controls (n=6) with spinal cord-injured (SCI) individuals (n=8) to assess the effects of long-term deconditioning. Subsequently, able-bodied controls underwent short-term lower limb deconditioning using 3 weeks of unilateral limb suspension. SCI individuals were examined before and after 6 weeks functional electrical stimulation exercise training. Baseline diameter and hyperemic flow were lower after short- and long-term deconditioning and higher after exercise training, whilst intima-media thickness/lumen ratio was increased with short- and long-term deconditioning and decreased with exercise training. Regarding gene expression levels of vasculature-related genes, we found that groups of genes including the vascular endothelial growth factor (VEGF) pathway, transforming growth factor beta 1 (TGFB1), and extracellular matrix (ECM) proteins strongly related with vascular adaptations in humans. This approach resulted in the identification of important genes that may be involved in vascular adaptations after physical deconditioning and exercise.
    Experimental physiology 10/2012; · 3.17 Impact Factor
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    ABSTRACT: We previously demonstrated that hexokinase (HK) II plays a key role in the pathophysiology of ischemia-reperfusion (I/R) injury of the heart (Smeele et al. Circ Res 108: 1165-1169, 2011; Wu et al. Circ Res 108: 60-69, 2011). However, it is unknown whether HKII also plays a key role in I/R injury and healing thereafter in skeletal muscle, and if so, through which mechanisms. We used male wild-type (WT) and heterozygous HKII knockout mice (HKII(+/-)) and performed in vivo unilateral skeletal muscle I/R, executed by 90 min hindlimb occlusion using orthodontic rubber bands followed by 1 h, 1 day, or 14 days reperfusion. The contralateral (CON) limb was used as internal control. No difference was observed in muscle glycogen turnover between genotypes at 1 h reperfusion. At 1 day reperfusion, the model resulted in 36% initial cell necrosis in WT gastrocnemius medialis (GM) muscle that was doubled (76% cell necrosis) in the HKII(+/-) mice. I/R-induced apoptosis (29%) was similar between genotypes. HKII reduction eliminated I/R-induced mitochondrial Bax translocation and oxidative stress at 1 day reperfusion. At 14 days recovery, the tetanic force deficit of the reperfused GM (relative to control GM) was 35% for WT, which was doubled (70%) in HKII(+/-) mice, mirroring the initial damage observed for these muscles. I/R increased muscle fatigue resistance equally in GM of both genotypes. The number of regenerating fibers in WT muscle (17%) was also approximately doubled in HKII(+/-) I/R muscle (44%), thus again mirroring the increased cell death in HKII(+/-) mice at day 1 and suggesting that HKII does not significantly affect muscle regeneration capacity. Reduced HKII was also associated with doubling of I/R-induced fibrosis. In conclusion, reduced muscle HKII protein content results in impaired muscle functionality during recovery from I/R. The impaired recovery seems to be mainly a result of a greater susceptibility of HKII(+/-) mice to the initial I/R-induced necrosis (not apoptosis), and not a HKII-related deficiency in muscle regeneration.
    Journal of Applied Physiology 06/2012; 113(4):608-18. · 3.48 Impact Factor
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    ABSTRACT: Wezenberg D, de Haan A, Faber WX, Slootman HJ, van der Woude LH, Houdijk H. Peak oxygen consumption in older adults with a lower limb amputation. OBJECTIVE: To investigate whether the aerobic capacity of older adults who underwent a lower limb amputation is associated with the presence, cause (traumatic or vascular), and level of amputation (transtibial or transfemoral). DESIGN: Cross-sectional descriptive. SETTING: Human motion laboratory at a rehabilitation center. PARTICIPANTS: Older subjects (n=36) who underwent lower limb amputation and age-matched, able-bodied controls (n=21). All subjects were able to walk for a minimum of 4 minutes. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Peak oxygen consumption (Vo(2)(peak)) was measured using open-circuit respirometry while performing a discontinuous, graded, 1-legged, peak cycle exercise test. RESULTS: After correcting for age, body mass index, and sex, the multiple linear regression analysis revealed that subjects who underwent amputation had a 13.1% lower aerobic capacity compared with able-bodied controls (P=.021). Differentiation among etiologies revealed that subjects with a vascular amputation had a lower Vo(2)(peak) of 29.1% compared with able-bodied controls (P<.001), whereas traumatic amputees did not differ from able-bodied controls (P=.127). After correcting for etiology, no association between level of amputation and Vo(2)(peak) was found (P=.534). CONCLUSIONS: Older adults who underwent an amputation because of vascular deficiency had a lower aerobic capacity compared with able-bodied controls and people with a traumatic amputation. The level of amputation was not associated with Vo(2)(peak).
    Archives of physical medicine and rehabilitation 06/2012; · 2.18 Impact Factor
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    ABSTRACT: Introduction: Ehlers-Danlos syndrome (EDS), a connective tissue disorder, may lead to impaired contractile function of lower limb muscles. Methods: To test this hypothesis and to understand the possible mechanisms involved, isometric function of the thigh muscles was investigated at different joint angles (30°, 60°, and 90° of knee flexion) in 7 tenascin-X (TNX)-deficient EDS patients. Results: There was reduced maximal voluntary torque of the knee extensors (but not knee flexors) across all joint angles in the patients. Time to reach maximal rate of torque development was delayed, and voluntary activation capacity was reduced in patients compared with controls, particularly at 30°. Conclusions: EDS is associated with muscle weakness, most likely due to increased compliance of the series-elastic component of muscle tissue and failure of maximal voluntary muscle activation. Further research is required to understand the influence of reduced voluntary activation on the severe fatigue reported by EDS patients. Muscle Nerve, 2012.
    Muscle & Nerve 06/2012; · 2.31 Impact Factor

Publication Stats

3k Citations
570.97 Total Impact Points


  • 2001–2014
    • Manchester Metropolitan University
      • • School of Healthcare Science
      • • Institute for Biomedical Research into Human Movement and Health
      Manchester, England, United Kingdom
  • 1989–2014
    • VU University Amsterdam
      • • Faculty of Human Movement Sciences
      • • Research Institute MOVE
      Amsterdamo, North Holland, Netherlands
  • 2007–2013
    • Radboud University Medical Centre (Radboudumc)
      • • Department of Neurology
      • • Department of Human Genetics
      Nymegen, Gelderland, Netherlands
  • 2011–2012
    • TNO
      • Expertise Group for Training and Performance Innovations
      Delft, South Holland, Netherlands
  • 1985–2011
    • University of Amsterdam
      • • Laboratory for Physiology
      • • Faculty of Humanities
      Amsterdamo, North Holland, Netherlands
  • 2010
    • Charité Universitätsmedizin Berlin
      • Zentrum für Muskel- und Knochenforschung (ZMK)
      Berlin, Land Berlin, Germany
  • 2005–2006
    • University of Birmingham
      • School of Sport and Exercise Sciences
      Birmingham, ENG, United Kingdom
  • 1997–2005
    • Radboud University Nijmegen
      • Department of Radiology
      Nijmegen, Provincie Gelderland, Netherlands