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Papers by henri roy

Biometrische Zeitschrift, 1967

der direkten und kollateralen Verwandtschaft (Rxa und Rxy) nach WRIGHT (1922), stutzt sich auf di... more der direkten und kollateralen Verwandtschaft (Rxa und Rxy) nach WRIGHT (1922), stutzt sich auf die f olgenden Formeln : Inzuchtkoeffizient: Fz = C [(!/2)*+*'+' (1 + Fa)] n = Anzahl Generationen zwischen der Elterngeneration und dem gemeinsamen Ahnen vaterlichern' = Anzahl Generationen zwischen der Elterngeneration und dem gemeinsamen Ahnen mutterlicherseits Fa = Inzuchtkoeffizient eines selbst ingezuchteten Inzuchtahnen R , , = Z(l/2)* l(1 + Fa)/(l + Pg n = Anzahl Generationen zwischen X und a Pa und PI: Inzuchtkoefhient des Ahnen a-.L-Direkte Verwandtschaft: bzw. des Nachkommen X Kollaterale Verwandtschaft : Rxy = C [(f,$)*+*' (1 + Fa)]/l(1 f. Fx) (1 + Py) n und n' wie fur Fx F a , Ex und F,: entsprechende Inzuchtkoeffizienten Fur jedes Pedigree (Abstammungstafel) konnen diese Formeln zur Berechnung der entsprechenden Werte Px, R,, und Rxp benutzt werden. Dal3 die Berechnungen oft sehr zeitaufwendig sind, weil3 jeder, der solche Analysen durchgefuhrt hat. Man kann nun einen Teil der notwendigen Berechnung vortabellieren und durch ein geeignetes Punktsystem mit den gesuchteii Werten verknupfen. WEBER (1961) hat fur die Berechnung des

Statistische Methoden der Populationsgenetik, 1960

In den bisherigen Abschnitten wurde die Gen- und Umweltwirkung analysiert, wobei jeweils von beka... more In den bisherigen Abschnitten wurde die Gen- und Umweltwirkung analysiert, wobei jeweils von bekannten Wirkungsgrosen ausgegangen wurde. Bei den quantitativen Merkmalen (die im allgemeinen durch Messen ermittelt werden) ist die beobachtete phanotypische Varianz eine Folge der kombinierten Umwelt- und Genotyp- bzw. Genwirkung. Der genetisch bedingte Merkmalswert wird durch die Umwelteffekte maskiert und kann als solcher nicht ermittelt werden. Das Interesse des Zuchters gilt jedoch fast ausschlieslich dem Genotyp, also der genetisch bedingten Merkmalspragung, indem allein genetisch bedingte Differenzen in der Merkmalspragung zuchterisch ausgewertet werden konnen. Umwelteffekte sind uber die Umweltgestaltung zu verandern und demgemas mit der Haltung, jedoch nicht mit der eigentlichen Zuchtung verknupft. Es ist deshalb zu unterscheiden zwischen Zuchtungserfolgen und Haltungserfolgen. Sofern die beobachtete Merkmalsvarianz zwischen den Individuen weitgehend auf Differenzen beruht, die genetischer Natur sind, kann durch Zuchtung diese Varianz ausgenutzt werden, das heist, wird es moglich, auf Grund bestimmter Zuchtungsverfahren mehrheitlich diejenigen Individuen zur Zucht auszuwahlen, die in gewunschter Richtung vererben, so das die Merkmalsverbesserung von Generation zu Generation genetischer Natur ist.

Statistische Methoden der Populationsgenetik, 1960

Die kunstliche Selektion ist nur sinnvoll, wenn sie auch zu einem Erfolg fuhrt. Es ist somit wich... more Die kunstliche Selektion ist nur sinnvoll, wenn sie auch zu einem Erfolg fuhrt. Es ist somit wichtig, zu wissen, von welchen Grosen dieser Erfolg abhangt (Lortscher 1954). Es sind dies 1. der Remontierungsprozentsatz, welcher die Selektionsintensitat nach oben begrenzt, 2. die Korrelation zwischen Phanotyp und Genotyp, 3. die genetisch bedingte Varianz der in Frage stehenden Merkmale, 4. die Anzahl der gleichzeitig berucksichtigten Merkmale und 5. die Konstanz der Selektion.

Statistische Methoden der Populationsgenetik, 1960

Spine, 2003

Study Design. Electromyographic and biomechanical methods were utilized to investigate correlatio... more Study Design. Electromyographic and biomechanical methods were utilized to investigate correlations between indexes of localized muscle fatigue and changes in the kinematics and kinetics of motion during a cyclic lifting task. Summary of Background Data. Recent advances in time-frequency analysis procedures for electromyographicic signal processing provide a new way of studying localized muscle fatigue during dynamic contractions. These methods provide a means to investigate fatiguerelated functional impairments in patients with low back pain. Objectives. To study the relationship between localized muscle fatigue and the biomechanics of lifting and lowering a weighted box. Fatigue-related changes in the electromyographicic signal of trunk and limb muscles were evaluated and compared to kinematic and kinetic measures in order to determine whether lifting strategy is modified with fatigue. Methods. A total of 14 healthy male subjects (26 Ϯ 5 years) cyclically lifted and lowered a 13 kg box (12 lifts/ min) for 4.5 minutes. A 5-second static maximum lifting task was included immediately before and after the cyclic lifting task to measure changes in lifting strength and static electromyographicic fatigue indexes. Electromyographic signals from 14 muscle sites (including paravertebral and limb muscles) were measured. Changes in the electromyographicic Instantaneous Median Frequency, a fatigue index, were computed using time-frequency analysis methods. This index was compared with more standardized measures of fatigue, such as those based on electromyographicic median frequency acquired during a static trunk extension test, subjective fatigue measures, and maximal static lifting strength. Biomechanical measures were gathered using a motion analysis system to study kinematic and kinetic changes during the lifting task. Results. During the cyclic lifting task, the electromyographic Instantaneous Median Frequency significantly decreased over time in the paravertebral muscles, but not in the limb muscles. Paravertebral electromyographicic Instantaneous Median Frequency changes were consistent with self-reports of fatigue as well as decreases in trunk extension strength. The magnitude of muscle-specific changes in electromyographicic Instantaneous Median Frequency was not significantly correlated with electromyographicic median frequency changes from the static trunk extension task. The load of the box relative to the maximal static lifting strength significantly affected the electromyographicic Instantaneous Median Frequency changes of paravertebral back muscles. Significant changes with fatigue during the task were found in the angular displacements at the knee, hip, trunk, and elbow. These biomechanical changes were associated with increased peak torque and forces at the L4-L5 vertebral segment. Conclusions. Our results demonstrate correlation between localized muscle fatigue and biomechanical adaptations that occur during a cyclic lifting task. This new technique may provide researchers and clinicians with a means to investigate fatigue-related effects of repetitive work tasks or assessment procedures that might be useful in improving education, lifting ergonomy, and back school programs. Although both the dynamic and static tasks resulted in spectral shifts in the electromyographicic data, the fact that these methods led to different musclespecific findings indicates that they should not be considered as equivalent assessment procedures.

Medicine & Science in Sports & Exercise, 2002

Purpose: To test the short-term and long-term reliability of time-frequency electromyographic (EM... more Purpose: To test the short-term and long-term reliability of time-frequency electromyographic (EMG) measures of fatigue during repetitive dynamic lifting and compare it with the reliability of median frequency (MF) EMG measures of fatigue during static lifting. Methods: Fourteen' healthy male subjects (26 Ϯ 5 years) repetitively (12 lifts/min) lifted and lowered a box (29 ϫ 25 ϫ 23 cm, 13 kg) for 4.5 min during 3 different tests on 2 different days. EMG data and the biomechanics of motion were recorded. Before and after dynamic lifting, static maximum lifting tests were performed. At the end of each of the two sessions, subjects performed a static lift at 80% of their maximum lifting force for 30 s. Results: Significant fatigue-related changes were observed during the lifting exercise via EMG time-frequency analysis at the paravertebral L5, L2, T10, and vastus lateralis (VL) electrode sites. Two parameters for assessing fatigue during dynamic contractions [i.e., the Instantaneous Median Frequency (IMDF) and its time dependent change] were shown to be reproducible both in the short-term (2 h) and long-term (2 wk). The corresponding ICCs reflecting the reproducibility of values between sessions were 96.9% (L5), 98.1% (L2), 90.1% (T10), 96.4% (UT), 98.0% (GM), 89.5% (VL), and 99.0% (BF), respectively. For most EMG recording sites, the reliability of the IMDF measures was not dependent upon the postural strategy that the subject used to accomplish the lifting task or on the subject's strength as measured via the static maximum lifting test. A comparison between the ICC values of the IMDF measures and those of the parameters utilized to assess fatigue during static sustained lifts [i.e., the Median Frequency (MDF) and its change during the test] revealed equally good reproducibility for most EMG recording sites. The respective ICC values that took into account time dependent trends for the IMDF parameter were 87.1% (L5), 62.4% (L2), 90.1% (T10), 0% (UT), 72.7% (GM), 45.4% (VL), and 100% (BF), and for the MDF parameter 94.9% (L5), 73.0% (L2), 80.9% (T10), 100% (UT), 89% (GM), 91.7% (VL), and 90.9% (BF), respectively. Conclusions: The time-frequency approach allows one to derive EMG spectral parameters that can be used to monitor muscle fatigue during dynamic real-world tasks such as lifting.

Biometrische Zeitschrift, 1967

der direkten und kollateralen Verwandtschaft (Rxa und Rxy) nach WRIGHT (1922), stutzt sich auf di... more der direkten und kollateralen Verwandtschaft (Rxa und Rxy) nach WRIGHT (1922), stutzt sich auf die f olgenden Formeln : Inzuchtkoeffizient: Fz = C [(!/2)*+*'+' (1 + Fa)] n = Anzahl Generationen zwischen der Elterngeneration und dem gemeinsamen Ahnen vaterlichern' = Anzahl Generationen zwischen der Elterngeneration und dem gemeinsamen Ahnen mutterlicherseits Fa = Inzuchtkoeffizient eines selbst ingezuchteten Inzuchtahnen R , , = Z(l/2)* l(1 + Fa)/(l + Pg n = Anzahl Generationen zwischen X und a Pa und PI: Inzuchtkoefhient des Ahnen a-.L-Direkte Verwandtschaft: bzw. des Nachkommen X Kollaterale Verwandtschaft : Rxy = C [(f,$)*+*' (1 + Fa)]/l(1 f. Fx) (1 + Py) n und n' wie fur Fx F a , Ex und F,: entsprechende Inzuchtkoeffizienten Fur jedes Pedigree (Abstammungstafel) konnen diese Formeln zur Berechnung der entsprechenden Werte Px, R,, und Rxp benutzt werden. Dal3 die Berechnungen oft sehr zeitaufwendig sind, weil3 jeder, der solche Analysen durchgefuhrt hat. Man kann nun einen Teil der notwendigen Berechnung vortabellieren und durch ein geeignetes Punktsystem mit den gesuchteii Werten verknupfen. WEBER (1961) hat fur die Berechnung des

Statistische Methoden der Populationsgenetik, 1960

In den bisherigen Abschnitten wurde die Gen- und Umweltwirkung analysiert, wobei jeweils von beka... more In den bisherigen Abschnitten wurde die Gen- und Umweltwirkung analysiert, wobei jeweils von bekannten Wirkungsgrosen ausgegangen wurde. Bei den quantitativen Merkmalen (die im allgemeinen durch Messen ermittelt werden) ist die beobachtete phanotypische Varianz eine Folge der kombinierten Umwelt- und Genotyp- bzw. Genwirkung. Der genetisch bedingte Merkmalswert wird durch die Umwelteffekte maskiert und kann als solcher nicht ermittelt werden. Das Interesse des Zuchters gilt jedoch fast ausschlieslich dem Genotyp, also der genetisch bedingten Merkmalspragung, indem allein genetisch bedingte Differenzen in der Merkmalspragung zuchterisch ausgewertet werden konnen. Umwelteffekte sind uber die Umweltgestaltung zu verandern und demgemas mit der Haltung, jedoch nicht mit der eigentlichen Zuchtung verknupft. Es ist deshalb zu unterscheiden zwischen Zuchtungserfolgen und Haltungserfolgen. Sofern die beobachtete Merkmalsvarianz zwischen den Individuen weitgehend auf Differenzen beruht, die genetischer Natur sind, kann durch Zuchtung diese Varianz ausgenutzt werden, das heist, wird es moglich, auf Grund bestimmter Zuchtungsverfahren mehrheitlich diejenigen Individuen zur Zucht auszuwahlen, die in gewunschter Richtung vererben, so das die Merkmalsverbesserung von Generation zu Generation genetischer Natur ist.

Statistische Methoden der Populationsgenetik, 1960

Die kunstliche Selektion ist nur sinnvoll, wenn sie auch zu einem Erfolg fuhrt. Es ist somit wich... more Die kunstliche Selektion ist nur sinnvoll, wenn sie auch zu einem Erfolg fuhrt. Es ist somit wichtig, zu wissen, von welchen Grosen dieser Erfolg abhangt (Lortscher 1954). Es sind dies 1. der Remontierungsprozentsatz, welcher die Selektionsintensitat nach oben begrenzt, 2. die Korrelation zwischen Phanotyp und Genotyp, 3. die genetisch bedingte Varianz der in Frage stehenden Merkmale, 4. die Anzahl der gleichzeitig berucksichtigten Merkmale und 5. die Konstanz der Selektion.

Statistische Methoden der Populationsgenetik, 1960

Spine, 2003

Study Design. Electromyographic and biomechanical methods were utilized to investigate correlatio... more Study Design. Electromyographic and biomechanical methods were utilized to investigate correlations between indexes of localized muscle fatigue and changes in the kinematics and kinetics of motion during a cyclic lifting task. Summary of Background Data. Recent advances in time-frequency analysis procedures for electromyographicic signal processing provide a new way of studying localized muscle fatigue during dynamic contractions. These methods provide a means to investigate fatiguerelated functional impairments in patients with low back pain. Objectives. To study the relationship between localized muscle fatigue and the biomechanics of lifting and lowering a weighted box. Fatigue-related changes in the electromyographicic signal of trunk and limb muscles were evaluated and compared to kinematic and kinetic measures in order to determine whether lifting strategy is modified with fatigue. Methods. A total of 14 healthy male subjects (26 Ϯ 5 years) cyclically lifted and lowered a 13 kg box (12 lifts/ min) for 4.5 minutes. A 5-second static maximum lifting task was included immediately before and after the cyclic lifting task to measure changes in lifting strength and static electromyographicic fatigue indexes. Electromyographic signals from 14 muscle sites (including paravertebral and limb muscles) were measured. Changes in the electromyographicic Instantaneous Median Frequency, a fatigue index, were computed using time-frequency analysis methods. This index was compared with more standardized measures of fatigue, such as those based on electromyographicic median frequency acquired during a static trunk extension test, subjective fatigue measures, and maximal static lifting strength. Biomechanical measures were gathered using a motion analysis system to study kinematic and kinetic changes during the lifting task. Results. During the cyclic lifting task, the electromyographic Instantaneous Median Frequency significantly decreased over time in the paravertebral muscles, but not in the limb muscles. Paravertebral electromyographicic Instantaneous Median Frequency changes were consistent with self-reports of fatigue as well as decreases in trunk extension strength. The magnitude of muscle-specific changes in electromyographicic Instantaneous Median Frequency was not significantly correlated with electromyographicic median frequency changes from the static trunk extension task. The load of the box relative to the maximal static lifting strength significantly affected the electromyographicic Instantaneous Median Frequency changes of paravertebral back muscles. Significant changes with fatigue during the task were found in the angular displacements at the knee, hip, trunk, and elbow. These biomechanical changes were associated with increased peak torque and forces at the L4-L5 vertebral segment. Conclusions. Our results demonstrate correlation between localized muscle fatigue and biomechanical adaptations that occur during a cyclic lifting task. This new technique may provide researchers and clinicians with a means to investigate fatigue-related effects of repetitive work tasks or assessment procedures that might be useful in improving education, lifting ergonomy, and back school programs. Although both the dynamic and static tasks resulted in spectral shifts in the electromyographicic data, the fact that these methods led to different musclespecific findings indicates that they should not be considered as equivalent assessment procedures.

Medicine & Science in Sports & Exercise, 2002

Purpose: To test the short-term and long-term reliability of time-frequency electromyographic (EM... more Purpose: To test the short-term and long-term reliability of time-frequency electromyographic (EMG) measures of fatigue during repetitive dynamic lifting and compare it with the reliability of median frequency (MF) EMG measures of fatigue during static lifting. Methods: Fourteen' healthy male subjects (26 Ϯ 5 years) repetitively (12 lifts/min) lifted and lowered a box (29 ϫ 25 ϫ 23 cm, 13 kg) for 4.5 min during 3 different tests on 2 different days. EMG data and the biomechanics of motion were recorded. Before and after dynamic lifting, static maximum lifting tests were performed. At the end of each of the two sessions, subjects performed a static lift at 80% of their maximum lifting force for 30 s. Results: Significant fatigue-related changes were observed during the lifting exercise via EMG time-frequency analysis at the paravertebral L5, L2, T10, and vastus lateralis (VL) electrode sites. Two parameters for assessing fatigue during dynamic contractions [i.e., the Instantaneous Median Frequency (IMDF) and its time dependent change] were shown to be reproducible both in the short-term (2 h) and long-term (2 wk). The corresponding ICCs reflecting the reproducibility of values between sessions were 96.9% (L5), 98.1% (L2), 90.1% (T10), 96.4% (UT), 98.0% (GM), 89.5% (VL), and 99.0% (BF), respectively. For most EMG recording sites, the reliability of the IMDF measures was not dependent upon the postural strategy that the subject used to accomplish the lifting task or on the subject's strength as measured via the static maximum lifting test. A comparison between the ICC values of the IMDF measures and those of the parameters utilized to assess fatigue during static sustained lifts [i.e., the Median Frequency (MDF) and its change during the test] revealed equally good reproducibility for most EMG recording sites. The respective ICC values that took into account time dependent trends for the IMDF parameter were 87.1% (L5), 62.4% (L2), 90.1% (T10), 0% (UT), 72.7% (GM), 45.4% (VL), and 100% (BF), and for the MDF parameter 94.9% (L5), 73.0% (L2), 80.9% (T10), 100% (UT), 89% (GM), 91.7% (VL), and 90.9% (BF), respectively. Conclusions: The time-frequency approach allows one to derive EMG spectral parameters that can be used to monitor muscle fatigue during dynamic real-world tasks such as lifting.