Carsten Müller

Publications (18) View all

• Article: The effect of individualized exercise interventions during treatment in pediatric patients with a malignant bone tumor.

  Corinna C Winter, Carsten Müller, Jendrik Hardes, Georg Gosheger, Joachim Boos, Dieter Rosenbaum
  [show abstract] [hide abstract]
  ABSTRACT: BACKGROUND: While research on exercise interventions during anticancer treatment is well-established in adults, only very few studies exist in children. However, pediatric patients experience great limitations to being physically active, and appropriate interventions are desired. PROCEDURE: The present study aimed at investigating the effects of individualized exercise interventions during inpatient stays on pediatric patients with a malignant bone tumor. The parameter of interest was physical activity (PA). Patients' PA during home stays was assessed 6 weeks as well as 3, 6, 12, and 18 months post-surgery. Patients were distinguished into an intervention group and a control group. All patients received endoprosthetic replacement of the affected bone in the same institution. RESULTS: A constant increase in all PA parameters was observed during follow-up. Exercise interventions were possible and appeared worthwhile. The intervention group showed better PA results at all measurements; however, no significant differences between groups were found. Furthermore, differences decreased especially after the cessation of the intervention. General problems in reaching appropriate power and compliance were observed. CONCLUSIONS: Individualized exercise interventions in pediatric bone tumor patients are possible and appear to be beneficial. Such interventions should be implemented in adjuvant care; however, future research is needed to understand more about the effects of different interventions.
  Supportive Care in Cancer 01/2013; · 2.09 Impact Factor
• Article: Validierung von neun Bewegungssensoren bei Kindern und jungen Erwachsenen

  Carsten Müller, Corinna Winter, Marie-Sophie Mogwitz, Dieter Rosenbaum
  [show abstract] [hide abstract]
  ABSTRACT: Zur Bestimmung der Messgenauigkeit handelsüblicher Bewegungssensoren wurden ein Akzelerometer und acht Pedometer von Schulkindern und jungen Erwachsenen unter kontrollierten Bedingungen und unter Alltagsbedingungen im Rahmen einer 24-stündigen Aktivitätsmessung getragen. Die präzisesten Ergebnisse unter kontrollierten Bedingungen wurden mit einem piezoelektrischen Pedometer erzielt. Die absoluten Abweichungen (Median) lagen für diesen Schrittzähler bei den Kindern zwischen 0,2 und 1,0%, bei den Erwachsenen zwischen 0,2 und 1,4%. Die absoluten Abweichungen für den Akzelerometer lagen zwischen 0,8 und 3,1% für die Schulkinder sowie zwischen 0,6 und 3,2% für die Erwachsenen. Die Messpräzision stieg unter kontrollierten Bedingungen mit zunehmender Bewegungsgeschwindigkeit an. Besonders bei den Schulkindern wiesen einige Schrittzähler mit Pendelarm-Mechanismus hohe absolute Abweichungen von über 50% auf. Die Unterschiede unter Alltagsbedingungen verdeutlichen, dass Schrittzahlangaben diverser Monitore nicht direkt miteinander verglichen werden können. In jedem Fall sollten Schrittzähler vor ihrem Einsatz in wissenschaftlichen Untersuchungen auf Gütekriterien wie Validität und Reliabilität gestestet werden. The purpose of this study was to determine the accuracy of one accelerometer and eight pedometers in schoolchildren and young adults under controlled experimental conditions and under free-living conditions over a 24-h period. The most accurate results under controlled conditions were obtained with a piezoelectric pedometer. For this device absolute deviations (median) ranged between 0.2 and 1.0% for children and between 0.2 and 1.4% for young adults. Absolute deviations for the accelerometer were 0.8–3.1% for children and 0.6–3.2% for adults. Motion sensors were more accurate with increasing walking speed. For several pedometers the absolute deviation exceeded 50% in tests with schoolchildren. These differing results illustrate that step counts from different motion sensors cannot be compared directly. Therefore, the validity and reliability of activity monitors should be examined carefully before being used in scientific research. SchlüsselwörterPedometer–Akzelerometer–Bewegungssensoren–Aktivitätserfassung–Piezoelektrischer Schrittzähler KeywordsPedometer–Accelerometer–Motion sensor–Physical activity assessment–Piezo-electric step counter
  Sportwissenschaft 04/2012; 41(1):8-15.
• Article: Prospective evaluation of physical activity in patients with idiopathic scoliosis or kyphosis receiving brace treatment.

  Carsten Müller, Katharina Fuchs, Corinna Winter, Dieter Rosenbaum, Carolin Schmidt, Viola Bullmann, Tobias L Schulte
  [show abstract] [hide abstract]
  ABSTRACT: Bracing is an established method of conservative treatment for adolescent idiopathic scoliosis and kyphosis. Compliance among adolescents is frequently inadequate due to the discomfort of wearing a brace, cosmetic issues, and fear on the part of patients and parents that bracing may reduce everyday physical activities. The aim of this prospective, controlled study was to objectify the impact of spinal bracing on daily step activity in patients receiving conservative treatment for adolescent idiopathic scoliosis (AIS) or adolescent kyphosis (AK). Forty-eight consecutive patients (mean age 13.4 ± 2.3 years), consisting of 38 AIS patients (33 girls, 5 boys) and 10 AK patients (6 girls, 4 boys) were included. Once the decision to carry out bracing had been taken and while the patients were waiting for the individual brace to be built, step activity was assessed without braces by means of step activity monitoring (SAM) for seven consecutive days. After 8 weeks of brace wearing, step activity was assessed during regular brace treatment, again for seven consecutive days. In addition, brace-wearing times were simultaneously recorded using temperature probes implanted in the braces to measure compliance. Before and during brace treatment, patients completed the Scoliosis Research Society (SRS-22) questionnaire. The SAM was worn for an average of 12.7 ± 1.5 h/day during the first measurement and 12.3 ± 1.9 h on average during the second measurement. The mean gait cycles (GCs) per day and per hour before treatment were 5,036 ± 1,465 and 395 ± 105, respectively. No significant reduction in step activity was found at the follow-up measurement during bracing, at 4,880 ± 1,529 GCs/day and 403 ± 144 GCs/h. Taking the 23-h recommended time for brace wearing as a basis (100%), patients wore the brace for 72.7 ± 27.6% of the prescribed time, indicating an acceptable level of compliance. Girls showed a higher compliance level (75.6 ± 25.6%) in comparison with boys (56.7 ± 31.9%), although the difference was not significant (P = 0.093). The SRS-22 total score showed no differences between the two measurements (2.57 ± 0.23 vs. 2.56 ± 0.28). Implementing a simultaneous and objective method of assessing step activity and brace-wearing times in everyday life proved to be feasible, and it expands the information available regarding the impact of bracing on patients' quality of life. The results clearly show that brace treatment does not negatively interfere with daily step activity in AIS and AK patients. This is an important finding that should help reduce patients' and parents' worries concerning bracing.
  European Spine Journal 04/2011; 20(7):1127-36. · 1.97 Impact Factor
• Article: Validition of nine motion sensors in children and young adults

  Carsten Müller, Corinna Winter, Marie-Sophie Mogwitz, Dieter Rosenbaum
  [show abstract] [hide abstract]
  ABSTRACT: The purpose of this study was to determine the accuracy of one accelerometer and eight pedometers in schoolchildren and young adults under controlled experimental conditions and under free-living conditions over a 24-h period. The most accurate results under controlled conditions were obtained with a piezoelectric pedometer. For this device absolute deviations (median) ranged between 0.2 and 1.0% for children and between 0.2 and 1.4% for young adults. Absolute deviations for the accelerometer were 0.8–3.1% for children and 0.6–3.2% for adults. Motion sensors were more accurate with increasing walking speed. For several pedometers the absolute deviation exceeded 50% in tests with schoolchildren. These differing results illustrate that step counts from different motion sensors cannot be compared directly. Therefore, the validity and reliability of activity monitors should be examined carefully before being used in scientific research.
  Sportwissenschaft 01/2011; 41:8-15.
• Article: Pediatric patients with a malignant bone tumor: when does functional assessment make sense?

  Corinna Caroline Winter, Carsten Müller, Jendrik Hardes, Joachim Boos, Georg Gosheger, Dieter Rosenbaum
  [show abstract] [hide abstract]
  ABSTRACT: The diagnosis of a malignant bone tumor in the lower limb is a risk factor for physical disability, limiting physical performance. Walking ability especially, which is essential for most activities of daily living, is limited in those patients. In the present study, the extent of limitations during the course of treatment was investigated to determine when the assessment of functional parameters is meaningful in those patients. In the present study, activity levels were determined in 20 patients with a malignant bone tumor in the lower limb who received endoprosthetic replacement of the affected bone and in 20 healthy individuals. A uniaxial accelerometer was used to investigate patients at five different time points after surgery. Patients performed significantly less amounts and intensities of activity than control individuals at all measurements. Significant increases in the volume of activity were observed after cessation of treatment. However, the intensity of activity only showed minor increases. Patients experiencing complications of surgery revealed greater restriction than those without even 18 months after surgery. After cessation of treatment for their disease, patients recovered markedly and showed great improvements in physical activity. However, some limitations appeared to persist. Comparisons with patients with longer follow-up revealed that meaningful functional assessment does not make sense within the first 12 months after surgery. More research is needed to show if longer follow-up periods reveal further improvements. Based on such information, it should be more promising to develop individually tailored activity recommendations and intervention programs.
  Supportive Care in Cancer 01/2011; 20(1):127-33. · 2.09 Impact Factor