Biomedical subjects

Kathleen J Ganley

Publications and source records attributed to Kathleen J Ganley.

5 recordsLinked to original sources

PubMed2005

Intersegmental dynamics during the swing phase of gait: a comparison of knee kinetics between 7 year-old children and adults.

Existing literature suggests that kinetic patterns associated with children's gait may not be adult-like until after 7 years of age. The development of adult-like kinetic patterns, especially those involving non-muscular interaction moments, occurs with time and experience. We tested the hypothesis that compared to adults, 7 year-old children would demonstrate a relatively larger contribution of muscle moment and a smaller contribution of interaction moment to the net knee joint moment during the swing phase of gait was tested. Net knee joint moments and the contributions of muscle and interaction moments to the net moments were compared between 7 year-old children and adults. Knee kinematics and net joint moments were similar between the two groups. Also, the contributions of the muscle and interaction moments to the net joint moment were similar (P > 0.05), suggesting that the ability to employ interaction moments during the swing phase of gait did not differ between the two groups.

Adult↗

PubMed2005

Gait kinematics and kinetics of 7-year-old children: a comparison to adults using age-specific anthropometric data.

The purpose of this study was to determine if sagittal plane gait kinematics and kinetics of 7-year-old children differed from those of adults when age-specific anthropometrics were used in the calculations. Joint angles, moments, and power obtained during level walking in 7-year-old children (n=15) were compared to data from adults (n=15). Calculations were performed using age-specific anthropometric data obtained from dual energy X-ray absorptiometry. For most of the variables examined, 7-year-olds were similar to adults, however children demonstrated a diminished peak plantar flexor moment and less peak power absorption and generation at the ankle during late stance. These results provide support for the hypothesis that children lack the neuromuscular maturity, especially at the ankle, to produce an adult-like gait pattern.

Adult↗

PubMed2005

Fuel oxidation during human walking.

Human adults walk at a characteristic speed, but the mechanisms responsible for this ubiquitous and reproducible behavior remain unknown. In this study, preferred walking speed (PWS) was 4.7 +/- 0.1 km h -1 in 12 overnight-fasted adults, mean age 30.0 +/- 2.6 years. Indirect calorimetry was used to measure fuel oxidation during level treadmill walking from 3.2 to 7.2 km h -1 progressively increased at increments of 0.8 km h -1 and 10.0-min intervals. Corroborating many previous reports, the O2 cost of transport (mL O2 kg -1 km -1 ) was numerically lowest at 4.8 km h -1 , near PWS, but was not significantly different than 5.6 km h -1 . The impact of walking speed on the fuel selection of skeletal muscle was much more dramatic. At speeds less than or equal to PWS, muscle carbohydrate (CHO) oxidation rates were quite low, in the range that could be matched by gluconeogenesis. Above 4.8 km h -1 , CHO oxidation rate increased abruptly and tracked the perception of effort (RPE). Stepwise linear regression revealed that CHO oxidation explained 70% of the variance in RPE, and speed provided an additional 4%. In contrast, the other variables included in the analysis, fat oxidation rate, heart rate, and O2 cost of transport, contributed no additional explained variance in RPE. We conclude that PWS is just below a threshold speed, above which CHO oxidation abruptly increases. The central nervous system may be guided by the perception of effort in selecting a PWS that minimizes dependence on CHO oxidation. We further conclude that skeletal muscle metabolic control is an important factor to be taken into account by the central nervous system motor control of human locomotion.

Adenosine Triphosphate↗

PubMed2004

Determination of lower extremity anthropometric parameters using dual energy X-ray absorptiometry: the influence on net joint moments during gait.

OBJECTIVE: The purpose of this study was threefold: (1) to report on a method of determining lower extremity anthropometric data using dual energy X-ray absorptiometry, (2) to compare values obtained with this method to predictions from cadaver-based estimates, and (3) to quantify the extent to which these data affect the calculation of net joint moments during walking. BACKGROUND: Anthropometric data used in inverse dynamics equations are often estimated from older cadaveric specimens. A practical method for determining population-specific data is needed. METHODS: Using DXA scans obtained from 20 healthy adults, the mass, center of mass, and moment of inertia of each lower extremity segment were determined and compared to cadaver-based estimates. In addition, gait analysis was performed on 10 of these subjects, and net joint moments (sagittal plane) were calculated at the ankle, knee, and hip using anthropometric data obtained from (a) DXA, and (b) cadaver-based estimates. RESULTS: Statistically significant differences were identified for DXA-derived and cadaver-based anthropometric values. Overall, moment curves computed using the two data sets differed more during the swing phase than during the stance of gait. CONCLUSIONS: DXA appears to be an appropriate method for obtaining population-specific anthropometric data. Moment calculations for activities involving high accelerations and no ground reaction forces (i.e. swing phase of gait, kicking, etc.) would be most influenced by the differences between the anthropometric data sets.

Absorptiometry, Photon↗

PubMed2004

Anthropometric parameters in children: a comparison of values obtained from dual energy x-ray absorptiometry and cadaver-based estimates.

Anthropometric data used in gait analysis for children are often estimated from older adult cadavers. The extent to which these estimates accurately represent children or affect the calculation of net joint moments during gait analysis is unknown. The purpose of this study was: (1) to compare dual energy X-ray absorptiometry (DXA)-derived anthropometric parameters to cadaver-based estimates in children, and (2) to determine if DXA-derived anthropometric data alter the results of gait analyses in children. Using DXA, the mass, center of mass location, and moment of inertia of the foot, shank, and thigh were obtained from 7 to 13 year-old children (n=50) and compared to cadaver-based estimates. Additionally, lower extremity net joint moments were calculated (inverse dynamics equations) for three children during gait using (a) DXA-derived, and (b) cadaver-based estimates of anthropometric parameters. Statistically significant differences were identified for most DXA-derived and cadaver-based anthropometric values. However, based on gait analysis of three children, it is likely that the differences between DXA-derived and cadaver-based anthropometric estimates would have a negligible effect on the calculation of net joint moments during gait in 7-13 year-old children.

Absorptiometry, Photon↗