Glide efficiency, the ability of a body to minimize deceleration over the glide, can change with variations in the body’s size and shape. The purpose of this study was to investigate the relationships between glide efficiency and the size and shape characteristics of swimmers. Eight male and eight female swimmers performed a series of horizontal glides at a depth of 70 cm below the surface. Glide efficiency parameters were calculated for velocities ranging from 1.4 to 1.6 m/s for female swimmers (and at the Reynolds number of 3.5 million) and from 1.6 to 1.8 m/s for male swimmers (and at the Reynolds number of 4.5 million). Several morphological indices were calculated to account for the shape characteristics, with the use of a photogrammetric method. Relationships between the variables of interest were explored with correlations, while repeated-measures ANOVA was used to assess within-group differences between different velocities for each gender group. Glide efficiency of swimmers increased when velocity decreased. Some morphological indices and postural angles showed a significant correlation with glide efficiency. The glide coefficient was significantly correlated to the chest to waist taper index for both gender groups. For the male group, the glide coefficient correlated significantly to the fineness ratio of upper body, the chest to hip cross-section. For the female group the glide coefficient had a significant correlation with the waist to hip taper index. The findings suggested that gliding efficiency was more dependent on shape characteristics and appropriate postural angles rather than being dependent on size characteristics.
Roozbeh Naemi, Stelios G. Psycharakis, Carla McCabe, Chris Connaboy and Ross H. Sanders
Jeffrey D. Holmes, David M. Andrews, Jennifer L. Durkin and James J. Dowling
The purpose of this study was to derive and validate regression equations for the prediction of fat mass (FM), lean mass (LM), wobbling mass (WM), and bone mineral content (BMC) of the thigh, leg, and leg + foot segments of living people from easily measured segmental anthropometric measures. The segment masses of 68 university-age participants (26 M, 42 F) were obtained from full-body dual photon x-ray absorptiometry (DXA) scans, and were used as the criterion values against which predicted masses were compared. Comprehensive anthropometric measures (6 lengths, 6 circumferences, 8 breadths, 4 skinfolds) were taken bilaterally for the thigh and leg for each person. Stepwise multiple linear regression was used to derive a prediction equation for each mass type and segment. Prediction equations exhibited high adjusted R 2 values in general (0.673 to 0.925), with higher correlations evident for the LM and WM equations than for FM and BMC. Predicted (equations) and measured (DXA) segment LM and WM were also found to be highly correlated (R 2 = 0.85 to 0.96), and FM and BMC to a lesser extent (R 2 = 0.49 to 0.78). Relative errors between predicted and measured masses ranged between 0.7% and –11.3% for all those in the validation sample (n = 16). These results on university-age men and women are encouraging and suggest that in vivo estimates of the soft tissue masses of the lower extremity can be made fairly accurately from simple segmental anthropometric measures.
Hans Kainz, Hoa X. Hoang, Chris Stockton, Roslyn R. Boyd, David G. Lloyd and Christopher P. Carty
the generic model to the individual’s anthropometry. Linear scaling methods use the ratios between the participant’s segment dimensions and that of the model to scale the generic model. 5 The participant’s segment dimensions are estimated from the three-dimensional (3D) location of experimental
Ilaria Masci, Giuseppe Vannozzi, Nancy Getchell and Aurelio Cappozzo
Assessing movement skills is a fundamental issue in motor development. Current process-oriented assessments, such as developmental sequences, are based on subjective judgments; if paired with quantitative assessments, a better understanding of movement performance and developmental change could be obtained. Our purpose was to examine the use of inertial sensors to evaluate developmental differences in hopping over distance. Forty children executed the task wearing the inertial sensor and relevant time durations and 3D accelerations were obtained. Subjects were also categorized in different developmental levels according to the hopping developmental sequence. Results indicated that some time and kinematic parameters changed with some developmental levels, possibly as a function of anthropometry and previous motor experience. We concluded that, since inertial sensors were suitable in describing hopping performance and sensitive to developmental changes, this technology is promising as an in-field and user-independent motor development assessment tool.
Ana F. Silva, Pedro Figueiredo, João Ribeiro, Francisco Alves, João Paulo Vilas-Boas, Ludovic Seifert and Ricardo J. Fernandes
To analyze young swimmers’ performance regarding sex and skill level, 23 boys and 26 girls (15.7 ± 0.8 and 14.5 ± 0.8 years old, respectively) were assessed for anthropometry, flexibility, strength, drag, coordination, and biomechanical variables. During a 50-m maximal front-crawl bout, seven aerial and six underwater Qualisys cameras assessed kinematics, and a load cell was used to measure drag (Tedea, United Kingdom) and tethered swimming force. A multivariate analysis of variance test (p < .05) enabled us to observe differences between skill levels in speed, stroke frequency, stroke index, and intracyclic velocity variations, but most relevant differences were noticed when comparing sexes, particularly for anthropometrics, shoulder flexibility, speed, stroke frequency, stroke length, drag, mechanical power, power per stroke, and maximal and mean force. Considering the included variables, only male swimmers’ performance could be predicted through multiple linear regression, with stroke index, left shoulder flexion, and intracycle velocity variations showing great importance in achieving better results.
Claudia Emes, Beth Velde, Mary Moreau, Douglas D. Murdoch and Rebecca Trussell
Two methods of introducing obese adolescents to aerobic exercise were compared. A fast-start group began with five aerobic sessions per week and gradually reduced these to three over a period of 12 weeks. A slow-start group began with one per week and gradually increased to three. A control group had an equivalent amount of time in interactive group sessions and nonaerobic activity. The program was assessed by physical fitness, anthropometry, and attendance. Results were analyzed by multivariate analysis. The method of introducing exercise to the subjects produced no significant differences on measures of fitness or anthropometry. Significant effects for time were shown for strength, push-ups, body mass index, the sum of five skinfolds, gluteal and abdominal circumferences, weight, and percent overweight. Significant differences in the absenteeism rates were shown among groups. However, no relationship was found between absenteeism and changes in weight or overall fitness levels.
H. Jan Dordel
Individuals with severe physical and psychomotor modifications after a brain injury need measures of motor training beyond the usual physiotherapy. The effects of an intensive mobility training in the phase of late rehabilitation are reported in two case studies. The coordinative and conditional progresses were controlled by the methods of photographic anthropometry, light-track registration, and bicycle ergometry. Improvements were found in posture and dynamic endurance in correlation with the generally improving motor control. Tests of everyday relevant movements revealed qualitative progresses in the sense of increased motor precision and economy.
Daniel das Virgens Chagas and Luiz Alberto Batista
Janeiro State University Ethics Committee and parental consent, and child assent was obtained prior to participation in research. Table 1 Descriptive Statistics of the Sample ( n = 69) Including Anthropometry, Physical Activity, and Motor Coordination Levels 12 Years ( n = 9) 13 Years ( n = 29) 14
Sarah M. Coppola, Philippe C. Dixon, Boyi Hu, Michael Y.C. Lin and Jack T. Dennerlein
. However, these differences were relatively small and may be related to unmeasured keyboard factors as the devices did not share the same form factors. Moreover, few of these studies have examined the effects on specific individual characteristics such as sex/gender, anthropometry, and strength. Previous
Stephen M. Glass, Brian L. Cone, Christopher K. Rhea, Donna M. Duffy and Scott E. Ross
differences in balance, for example, by identifying and subtracting linear trends related to height. 23 , 24 However, recent evidence suggests that associations between postural sway and individual anthropometry differ by sex, not to mention other factors, such as stance condition. 25 , 26 These potentially