ObjectivesFatigue can decrease knee stability and increase the injury risk. However, fatigue is r... more ObjectivesFatigue can decrease knee stability and increase the injury risk. However, fatigue is rarely being applied throughout movement analysis. The aim of this study was to investigate if the knee stability throughout SLDLs differ between cyclic and acyclic sports, before and after fatigue in general, and between the dominant and non-dominant leg of soccer players.MethodsA total of 43 active male (n = 34) and female (n = 9) athletes (age: 26.5 ± 7.2) participated in this study with a pre-post-design. Subjects performed a single leg drop landing (SLDL) from a plyobox. For each leg, the two-dimensional frontal plane projection angle (FPPA) was analyzed. After pretesting the shuttle run test was performed until exhaustion, before repeating the measurements.ResultsANOVA with repeated measures was applied and identified no significance difference for the FPPA between cyclic and acyclic sports (F = 0.98, p = 0.33), a significant difference before and after fatigue (F = 12.49, p = 0.002...
Position statement and updated international guideline for safe and effective whole-body electrom... more Position statement and updated international guideline for safe and effective whole-body electromyostimulation training-the need for common sense in WB-EMS application.
Whole-Body Electromyostimulation (WB-EMS) is a training technology that enables simultaneous stim... more Whole-Body Electromyostimulation (WB-EMS) is a training technology that enables simultaneous stimulation of all the main muscle groups with a specific impulse intensity for each electrode. The corresponding time-efficiency and joint-friendliness of WB-EMS may be particularly attractive for people unable or unmotivated to conduct (intense) conventional training protocols. However, due to the enormous metabolic and musculoskeletal impact of WB-EMS, particular attention must be paid to the application of this technology. In the past, several scientific and newspaper articles reported severe adverse effects of WB-EMS. To increase the safety of commercial non-medical WB-EMS application, recommendations “for safe and effective whole-body electromyostimulation” were launched in 2016. However, new developments and trends require an update of these recommendations to incorporate more international expertise with demonstrated experience in the application of WB-EMS. The new version of these c...
Handgrip strength (HGS) appears to be an indicator of climbing performance. The transferability o... more Handgrip strength (HGS) appears to be an indicator of climbing performance. The transferability of HGS measurements obtained using a hand dynamometer and factors that influence the maximal climbing-specific holding time (CSHT) are largely unclear. Forty-eight healthy subjects (27 female, 21 male; age: 22.46 ± 3.17 years; height: 172.76 ± 8.91 cm; weight: 69.07 ± 12.41 kg; body fat: 20.05% ± 7.95%) underwent a maximal pull-up test prior to the experiment and completed a self-assessment using a Likert scale questionnaire. HGS was measured using a hand dynamometer, whereas CSHT was measured using a fingerboard. Multiple linear regressions showed that weight, maximal number of pull-ups, HGS normalized by subject weight, and length of the middle finger had a significant effect on the maximal CSHT (non-dominant hand: R2corr = 0.63; dominant hand: R2corr = 0.55). Deeper exploration using a machine learning model including all available data showed a predictive performance with R2 = 0.51 an...
International Journal of Environmental Research and Public Health
Poor posture is a well-known problem in all age groups and can lead to back pain, which in turn c... more Poor posture is a well-known problem in all age groups and can lead to back pain, which in turn can result in high socio-economic costs. Regular assessment of posture can therefore help to identify postural deficits at an early stage in order to take preventive measures and can therefore be an important tool for promoting public health. We measured the posture of 1127 symptom-free subjects aged 10 to 69 years using stereophotogrammetry and determined the sagittal posture parameters flèche cervicale (FC), flèche lombaire (FL), and kyphosis index (KI) as well as the values standardized to the trunk height (FC%, FL%, KI%). FC, FC%, KI, and KI% showed an increase with age in men but not in women, and a difference between the sexes. FL remained largely constant with age, although FL% had significantly greater values in women than men. Postural parameters correlated only moderately or weakly with body mass index. Reference values were determined for different age groups and for both sexes...
Sportverletzung Sportschaden : Organ der Gesellschaft für Orthopädisch-Traumatologische Sportmedizin, 2016
Lesions/irritations of the obturator internus muscle (OIM) are rare, several differential diagnos... more Lesions/irritations of the obturator internus muscle (OIM) are rare, several differential diagnoses are possible. This paper describes the case of an OIM injury in a professional football player. On clinical examination, painful internal rotation of the hip joint was an indication for a lesion/irritation of the OIM. MRI was the procedure of choice for imaging. Movement analysis served to detect a functional malposition. A short recovery time requires functional treatment as well as the use of orthopaedic aids to correct possible deformities.
Although the influence of muscle activity on the pelvic position has been proven, research on the... more Although the influence of muscle activity on the pelvic position has been proven, research on the influence of (asymmetric) muscle fatigue on the pelvic position is inconsistent. The purpose of the present study was to assess the effects of asymmetric fatigue of the lateral trunk muscles on the pelvic position based on a pre/post/follow-up design. For the final data analysis, 38 subjects (20 men, 18 women; age 22.63 ± 3.91 years) were asked to perform side bends in sets of 20 repetitions on a Roman chair until complete exhaustion. For pre-, post-, and follow-up test (24 h after treatment), pelvic positions were recorded with a 3D photogrammetric scan. Statistical analysis showed no systematic changes in pelvic inclination and rotation after unilateral exhaustion for the three measuring times. However, highly individual, non-systematic changes in pelvic positions were present, especially between pre- and post-test. The follow-up measurements tend to return to the initial pre-test sta...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Introduction: Non-contact thermography enables the diagnosis of the distribution of skin surface ... more Introduction: Non-contact thermography enables the diagnosis of the distribution of skin surface temperature during athletic movement. Resistance exercise results in stress of required musculature, which is supposed to be measurable thermographically in terms of skin surface temperature change. Objective: This study aims to evaluate the application of thermography to analyze changes in skin temperature, representing specific muscle groups, during and after resistance
Introduction: Non-contact thermography enables the diagnosis of the distribution of skin surface ... more Introduction: Non-contact thermography enables the diagnosis of the distribution of skin surface temperature during athletic movement. Resistance exercise results in stress of required musculature, which is supposed to be measurable thermographically in terms of skin surface temperature change. Objective: This study aims to evaluate the application of thermography to analyze changes in skin temperature, representing specific muscle groups, during and after resistance
The objectification of acute fatigue (during isometric muscle contraction) and cumulative fatigue... more The objectification of acute fatigue (during isometric muscle contraction) and cumulative fatigue (due to multiple intermittent isometric muscle contractions) plays an important role in sport climbing. The data of 42 participants were used in the study. Climbing performance was operationalized using maximal climbing-specific holding time (CSHT) by performing dead hangs. The test started with an initial measurement of handgrip strength (HGS) followed by three intermittent measurements of CSHT and HGS. During the test, finger flexor muscle oxygen saturation (SmO2) was measured using a near-infrared spectroscopy wearable biosensor. Significant reductions in CSHT and HGS could be found (p < 0.001), which indicates that the consecutive maximal isometric holding introduces cumulative fatigue. The reduction in CSHT did not correlate with a reduction in HGS over multiple consecutive maximal dead hangs (p > 0.35). Furthermore, there were no significant differences in initial SmO2 level...
Soccer and football players are exposed to a high risk of groin pain. In some cases, the pubic sy... more Soccer and football players are exposed to a high risk of groin pain. In some cases, the pubic symphysis is the origin of the problems.This article presents a case report of a young elite soccer player who, over a period of two years, suffered from pain in the groin and symphysis area. The right leg was the kicking leg. Imaging techniques did not reveal pathological findings. Sports hernia, osteomyelitis, enthesopathy, adductor tendonitis, and muscle sprains, as well as rheumatic or urogenital disorders were excluded.A 3 D posture analysis was performed to examine the statics of the body and pelvis. The maximum isometric strength of the left and right leg adductors and abductors, as well as the knee flexors and extensors were measured.We found a muscular imbalance resulting from the type of sport the athlete engaged in with an unfavourable ratio between the right knee extensor and flexor muscles. Comparing sides, an imbalance was also identified between the right and left knee extensor. This imbalance resulted in a one-sided forward tilt of the right hemi-pelvis. This pelvic torsion may lead to an increase in shear forces in the pubic symphysis, which we suspected to be the reason for the recurring problems.After three months of specific training exercises, the pelvic position was harmonised and the muscular imbalances were significantly reduced. Even 6 months after completion of the specific training exercises, the player remained without complaints despite his unvaried soccer training intensity.Causal treatment of functional pain in the groin or symphysis area should take into account the ipsilateral and contralateral strength ratios of the knee extensors and flexors as well as the three-dimensional position of the pelvis.
International Journal of Kinesiology and Sports Science, 2015
Introduction: Infrared thermography (IRT) is a non-invasive, non-contact procedure for skin surfa... more Introduction: Infrared thermography (IRT) is a non-invasive, non-contact procedure for skin surface temperature (SST) diagnostics and represents an effective, safe, and relatively cost-effective diagnosis tool for estimating the SST. While IRT has been established as a diagnosis tool in numerous medical areas of application, it is still in its initial stages as regards to sports science. We will therefore examine the extent to which IRT can be used for diagnosing the SST after a 10-minute warm-up phase. Method: 20 male sports students (23.0 ± 1.6 years; 75.8 ± 9.0 kg; 181.0 ± 6.8 cm) participated in this study. After a standardized preparation phase, the SST of the lower and upper extremities as well as the trunk was determined in a resting state. This was followed by a 10-minute warm-up phase on a bike ergometer set to 1.5 W/kg body weight and a cadence of 60-80 rpm. After the warm-up, the SST was determined again for the 1st to 10th minute of the post-strain phase. Results: The 10-minute warm-up resulted in a significant change in the SST over the time of measurement (P < 0.05; η 2 p = 0.16). Furthermore, a significant difference of the SST among the different areas of the body was identified (P < 0.05; η 2 p = 0.15). The interaction between the time and the area of measurement was also significant (P < 0.05; η 2 p = 0.16). The drop in SST from resting state to the first measurement after the 10minute warm-up phase was 1.16°C and 3.7% in the trunk musculature. The temperature of the arm musculature dropped by 0.59°C (1.9%), while the temperature of the leg musculature decreased by 1.12°C (3.6%). Ten minutes after the warm-up, the SST of legs and arms was back at the initial state before the strain, but the trunk SST was still 0.74°C (2.3%) lower. Discussion: IRT shows a characteristic SST progression after muscular warm-up. Different SSTs occur depending on the body area, which needs to be considered for standardized warm-ups on the bike ergometer.
The present study aimed to assess the effects of asymmetric muscle fatigue on the skin surface te... more The present study aimed to assess the effects of asymmetric muscle fatigue on the skin surface temperature of abdominal and back muscles. The study was based on a pre-post/follow-up design with one group and included a total of 41 subjects (22 male, 19 female; age, 22.63 ± 3.91; weight, 71.89 ± 12.97 kg; height, 173.36 ± 9.95). All the participants were asked to perform side bends in sets of 20 repetitions on a Roman chair until complete exhaustion. The pre-, post- and follow-up test (24 h after) skin surface temperatures were recorded with infrared thermography. Subjective muscle soreness and muscle fatigue were analyzed using two questionnaires. The results of the post hoc tests showed that skin temperature was statistically significantly lower in the post-tests than in the pre- and follow-up tests, but no meaningful differences existed between the pre- and follow-up tests. Asymmetric side differences were found in the post-test for the upper and lower areas of the back. Differenc...
Abstract: Background: Increased anterior pelvic tilt is one important contributor to poor posture... more Abstract: Background: Increased anterior pelvic tilt is one important contributor to poor posture in children and adolescents and caused by muscular imbalance. This study aims at identifying the extent to which a sensorimotor training reduces anterior pelvic tilt more effectively than pure strength and stretch training alone. Methods: 54 male adolescents (age 13-17) with an increased pelvic tilt angle >14° were matched to three groups (strength training STR, strength + sensorimotor training STR + SENS, control CON). Maximum isometric torques for knee flexion (HA), trunk flexion (RA), and trunk extension, and pelvic tilt were measured before and after a 12 week physical therapy schedule. Two-way mixed ANOVA were calculated. Results: For STR and STR + SENS the relative torque of HA and RA increased significantly (p < 0.05) between pre-and post-test. Significant improvement of the pelvic tilt angle was identified in both training groups, with STR + SENS exhibiting a significantly...
ObjectivesFatigue can decrease knee stability and increase the injury risk. However, fatigue is r... more ObjectivesFatigue can decrease knee stability and increase the injury risk. However, fatigue is rarely being applied throughout movement analysis. The aim of this study was to investigate if the knee stability throughout SLDLs differ between cyclic and acyclic sports, before and after fatigue in general, and between the dominant and non-dominant leg of soccer players.MethodsA total of 43 active male (n = 34) and female (n = 9) athletes (age: 26.5 ± 7.2) participated in this study with a pre-post-design. Subjects performed a single leg drop landing (SLDL) from a plyobox. For each leg, the two-dimensional frontal plane projection angle (FPPA) was analyzed. After pretesting the shuttle run test was performed until exhaustion, before repeating the measurements.ResultsANOVA with repeated measures was applied and identified no significance difference for the FPPA between cyclic and acyclic sports (F = 0.98, p = 0.33), a significant difference before and after fatigue (F = 12.49, p = 0.002...
Position statement and updated international guideline for safe and effective whole-body electrom... more Position statement and updated international guideline for safe and effective whole-body electromyostimulation training-the need for common sense in WB-EMS application.
Whole-Body Electromyostimulation (WB-EMS) is a training technology that enables simultaneous stim... more Whole-Body Electromyostimulation (WB-EMS) is a training technology that enables simultaneous stimulation of all the main muscle groups with a specific impulse intensity for each electrode. The corresponding time-efficiency and joint-friendliness of WB-EMS may be particularly attractive for people unable or unmotivated to conduct (intense) conventional training protocols. However, due to the enormous metabolic and musculoskeletal impact of WB-EMS, particular attention must be paid to the application of this technology. In the past, several scientific and newspaper articles reported severe adverse effects of WB-EMS. To increase the safety of commercial non-medical WB-EMS application, recommendations “for safe and effective whole-body electromyostimulation” were launched in 2016. However, new developments and trends require an update of these recommendations to incorporate more international expertise with demonstrated experience in the application of WB-EMS. The new version of these c...
Handgrip strength (HGS) appears to be an indicator of climbing performance. The transferability o... more Handgrip strength (HGS) appears to be an indicator of climbing performance. The transferability of HGS measurements obtained using a hand dynamometer and factors that influence the maximal climbing-specific holding time (CSHT) are largely unclear. Forty-eight healthy subjects (27 female, 21 male; age: 22.46 ± 3.17 years; height: 172.76 ± 8.91 cm; weight: 69.07 ± 12.41 kg; body fat: 20.05% ± 7.95%) underwent a maximal pull-up test prior to the experiment and completed a self-assessment using a Likert scale questionnaire. HGS was measured using a hand dynamometer, whereas CSHT was measured using a fingerboard. Multiple linear regressions showed that weight, maximal number of pull-ups, HGS normalized by subject weight, and length of the middle finger had a significant effect on the maximal CSHT (non-dominant hand: R2corr = 0.63; dominant hand: R2corr = 0.55). Deeper exploration using a machine learning model including all available data showed a predictive performance with R2 = 0.51 an...
International Journal of Environmental Research and Public Health
Poor posture is a well-known problem in all age groups and can lead to back pain, which in turn c... more Poor posture is a well-known problem in all age groups and can lead to back pain, which in turn can result in high socio-economic costs. Regular assessment of posture can therefore help to identify postural deficits at an early stage in order to take preventive measures and can therefore be an important tool for promoting public health. We measured the posture of 1127 symptom-free subjects aged 10 to 69 years using stereophotogrammetry and determined the sagittal posture parameters flèche cervicale (FC), flèche lombaire (FL), and kyphosis index (KI) as well as the values standardized to the trunk height (FC%, FL%, KI%). FC, FC%, KI, and KI% showed an increase with age in men but not in women, and a difference between the sexes. FL remained largely constant with age, although FL% had significantly greater values in women than men. Postural parameters correlated only moderately or weakly with body mass index. Reference values were determined for different age groups and for both sexes...
Sportverletzung Sportschaden : Organ der Gesellschaft für Orthopädisch-Traumatologische Sportmedizin, 2016
Lesions/irritations of the obturator internus muscle (OIM) are rare, several differential diagnos... more Lesions/irritations of the obturator internus muscle (OIM) are rare, several differential diagnoses are possible. This paper describes the case of an OIM injury in a professional football player. On clinical examination, painful internal rotation of the hip joint was an indication for a lesion/irritation of the OIM. MRI was the procedure of choice for imaging. Movement analysis served to detect a functional malposition. A short recovery time requires functional treatment as well as the use of orthopaedic aids to correct possible deformities.
Although the influence of muscle activity on the pelvic position has been proven, research on the... more Although the influence of muscle activity on the pelvic position has been proven, research on the influence of (asymmetric) muscle fatigue on the pelvic position is inconsistent. The purpose of the present study was to assess the effects of asymmetric fatigue of the lateral trunk muscles on the pelvic position based on a pre/post/follow-up design. For the final data analysis, 38 subjects (20 men, 18 women; age 22.63 ± 3.91 years) were asked to perform side bends in sets of 20 repetitions on a Roman chair until complete exhaustion. For pre-, post-, and follow-up test (24 h after treatment), pelvic positions were recorded with a 3D photogrammetric scan. Statistical analysis showed no systematic changes in pelvic inclination and rotation after unilateral exhaustion for the three measuring times. However, highly individual, non-systematic changes in pelvic positions were present, especially between pre- and post-test. The follow-up measurements tend to return to the initial pre-test sta...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Introduction: Non-contact thermography enables the diagnosis of the distribution of skin surface ... more Introduction: Non-contact thermography enables the diagnosis of the distribution of skin surface temperature during athletic movement. Resistance exercise results in stress of required musculature, which is supposed to be measurable thermographically in terms of skin surface temperature change. Objective: This study aims to evaluate the application of thermography to analyze changes in skin temperature, representing specific muscle groups, during and after resistance
Introduction: Non-contact thermography enables the diagnosis of the distribution of skin surface ... more Introduction: Non-contact thermography enables the diagnosis of the distribution of skin surface temperature during athletic movement. Resistance exercise results in stress of required musculature, which is supposed to be measurable thermographically in terms of skin surface temperature change. Objective: This study aims to evaluate the application of thermography to analyze changes in skin temperature, representing specific muscle groups, during and after resistance
The objectification of acute fatigue (during isometric muscle contraction) and cumulative fatigue... more The objectification of acute fatigue (during isometric muscle contraction) and cumulative fatigue (due to multiple intermittent isometric muscle contractions) plays an important role in sport climbing. The data of 42 participants were used in the study. Climbing performance was operationalized using maximal climbing-specific holding time (CSHT) by performing dead hangs. The test started with an initial measurement of handgrip strength (HGS) followed by three intermittent measurements of CSHT and HGS. During the test, finger flexor muscle oxygen saturation (SmO2) was measured using a near-infrared spectroscopy wearable biosensor. Significant reductions in CSHT and HGS could be found (p < 0.001), which indicates that the consecutive maximal isometric holding introduces cumulative fatigue. The reduction in CSHT did not correlate with a reduction in HGS over multiple consecutive maximal dead hangs (p > 0.35). Furthermore, there were no significant differences in initial SmO2 level...
Soccer and football players are exposed to a high risk of groin pain. In some cases, the pubic sy... more Soccer and football players are exposed to a high risk of groin pain. In some cases, the pubic symphysis is the origin of the problems.This article presents a case report of a young elite soccer player who, over a period of two years, suffered from pain in the groin and symphysis area. The right leg was the kicking leg. Imaging techniques did not reveal pathological findings. Sports hernia, osteomyelitis, enthesopathy, adductor tendonitis, and muscle sprains, as well as rheumatic or urogenital disorders were excluded.A 3 D posture analysis was performed to examine the statics of the body and pelvis. The maximum isometric strength of the left and right leg adductors and abductors, as well as the knee flexors and extensors were measured.We found a muscular imbalance resulting from the type of sport the athlete engaged in with an unfavourable ratio between the right knee extensor and flexor muscles. Comparing sides, an imbalance was also identified between the right and left knee extensor. This imbalance resulted in a one-sided forward tilt of the right hemi-pelvis. This pelvic torsion may lead to an increase in shear forces in the pubic symphysis, which we suspected to be the reason for the recurring problems.After three months of specific training exercises, the pelvic position was harmonised and the muscular imbalances were significantly reduced. Even 6 months after completion of the specific training exercises, the player remained without complaints despite his unvaried soccer training intensity.Causal treatment of functional pain in the groin or symphysis area should take into account the ipsilateral and contralateral strength ratios of the knee extensors and flexors as well as the three-dimensional position of the pelvis.
International Journal of Kinesiology and Sports Science, 2015
Introduction: Infrared thermography (IRT) is a non-invasive, non-contact procedure for skin surfa... more Introduction: Infrared thermography (IRT) is a non-invasive, non-contact procedure for skin surface temperature (SST) diagnostics and represents an effective, safe, and relatively cost-effective diagnosis tool for estimating the SST. While IRT has been established as a diagnosis tool in numerous medical areas of application, it is still in its initial stages as regards to sports science. We will therefore examine the extent to which IRT can be used for diagnosing the SST after a 10-minute warm-up phase. Method: 20 male sports students (23.0 ± 1.6 years; 75.8 ± 9.0 kg; 181.0 ± 6.8 cm) participated in this study. After a standardized preparation phase, the SST of the lower and upper extremities as well as the trunk was determined in a resting state. This was followed by a 10-minute warm-up phase on a bike ergometer set to 1.5 W/kg body weight and a cadence of 60-80 rpm. After the warm-up, the SST was determined again for the 1st to 10th minute of the post-strain phase. Results: The 10-minute warm-up resulted in a significant change in the SST over the time of measurement (P < 0.05; η 2 p = 0.16). Furthermore, a significant difference of the SST among the different areas of the body was identified (P < 0.05; η 2 p = 0.15). The interaction between the time and the area of measurement was also significant (P < 0.05; η 2 p = 0.16). The drop in SST from resting state to the first measurement after the 10minute warm-up phase was 1.16°C and 3.7% in the trunk musculature. The temperature of the arm musculature dropped by 0.59°C (1.9%), while the temperature of the leg musculature decreased by 1.12°C (3.6%). Ten minutes after the warm-up, the SST of legs and arms was back at the initial state before the strain, but the trunk SST was still 0.74°C (2.3%) lower. Discussion: IRT shows a characteristic SST progression after muscular warm-up. Different SSTs occur depending on the body area, which needs to be considered for standardized warm-ups on the bike ergometer.
The present study aimed to assess the effects of asymmetric muscle fatigue on the skin surface te... more The present study aimed to assess the effects of asymmetric muscle fatigue on the skin surface temperature of abdominal and back muscles. The study was based on a pre-post/follow-up design with one group and included a total of 41 subjects (22 male, 19 female; age, 22.63 ± 3.91; weight, 71.89 ± 12.97 kg; height, 173.36 ± 9.95). All the participants were asked to perform side bends in sets of 20 repetitions on a Roman chair until complete exhaustion. The pre-, post- and follow-up test (24 h after) skin surface temperatures were recorded with infrared thermography. Subjective muscle soreness and muscle fatigue were analyzed using two questionnaires. The results of the post hoc tests showed that skin temperature was statistically significantly lower in the post-tests than in the pre- and follow-up tests, but no meaningful differences existed between the pre- and follow-up tests. Asymmetric side differences were found in the post-test for the upper and lower areas of the back. Differenc...
Abstract: Background: Increased anterior pelvic tilt is one important contributor to poor posture... more Abstract: Background: Increased anterior pelvic tilt is one important contributor to poor posture in children and adolescents and caused by muscular imbalance. This study aims at identifying the extent to which a sensorimotor training reduces anterior pelvic tilt more effectively than pure strength and stretch training alone. Methods: 54 male adolescents (age 13-17) with an increased pelvic tilt angle >14° were matched to three groups (strength training STR, strength + sensorimotor training STR + SENS, control CON). Maximum isometric torques for knee flexion (HA), trunk flexion (RA), and trunk extension, and pelvic tilt were measured before and after a 12 week physical therapy schedule. Two-way mixed ANOVA were calculated. Results: For STR and STR + SENS the relative torque of HA and RA increased significantly (p < 0.05) between pre-and post-test. Significant improvement of the pelvic tilt angle was identified in both training groups, with STR + SENS exhibiting a significantly...
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