A new air displacement method for the determination of human body composition.

A new device based on the plethysmographic measurement of body volume has been developed for the purpose of estimating human body composition. The device, the BOD POD Body Composition System, uses the relationship between pressure and volume to derive the body volume of a subject seated inside a fiberglass chamber. Derivation of body volume, together with measurement of body mass, permits calculation of body density and subsequent estimation of percent fat and fat-free mass. Critical issues which have hampered prior plethysmographic approaches are discussed. The present system's ability to measure the volume of inanimate objects was evaluated for accuracy, reliability, and linearity. Twenty successive tests of a known volume (50,039 ml) on two separate days produced values of 50,037 +/- 12.7 ml and 50,030 +/- 13.5 ml (mean +/- SD) for each day, respectively. The CV for these series were 0.025% and 0.027%. Further testing across a wide range of volumes approximating human size (25-150 1) produced the following regression equation where y = measured volume (1) and x = actual volume (1): y = 0.9998x - 0.0274, r2 = 1.0, SEE = 0.004 1. The resultant device is likely to enhance opportunities for the quick, simple and noninvasive measurement of body composition for both research and clinical applications.

Validación de un método kineantropométrico: estudio de una muestra de deportistas chilenos de alto rendimiento / Validation of kineanthropometrical method: study in a group of chilean athletes of high performance

Una de las ciencias aplicadas al deporte es la kineantropometría. Cumple un rol importante al generar una interfase cuantitativa entre anatomía y rendimiento. La composición corporal (CC) proporciona importante información, en lo que respecta a los porcentajes de masa muscular (por ciento) y masa grasa (por ciento). Históricamente, se ha empleado la densitometría como patrón oro en la obtención de los modelos CC. Desde 1984, año de realización del estudio de cadáveres de Bruselas, han sido estos resultados los utilizados como patrón para la validación de los métodos CC. El método de fraccionamiento corporal de Deborah Kerr es el único método kineantropométrico que cumple con las 3 condiciones que la Sociedad Internacional para Avances en Kineantropometría (ISAK-1986), sugiere para validar un método. Dicho método calcula las masas de los tejidos de piel, graso, muscular, óseo y residual, en forma separada, obteniendo correlaciones estadísticamente significativas con respecto a masas corporales observadas en el estudio de Bruselas. La validación de este método en una muestra de deportistas chilenos de alto rendimiento, además de dar a conocer este nuevo método a la comunidad científica nacional, nos permitiría contar con antecedentes confiables en la utilización de éste al aplicarlo en los programas científico-deportivos. Utilizando un estudio hecho con los deportistas top de DIGEDER, se consideraron los pesos obtenidos en la balanza (PO) y los pesos estructurados (PE) o calculados por el método de Kerr (1988), siguiendo los protocolos de medición de la ISAK, de 121 deportistas de alto rendimiento nacional, 88 varones y 33 damas, para realizar una correlación según "r" de Pearson entre ambas variables. Se consideraron como parámetros estadísticos de importancia, al error constante (CE) absoluto y relativo, el error total (TE) y el coeficiente de determinación (i²). Los resultados muestran correlaciones entre 0,88 y 0,99 (p< 0,001) con coeficientes de determinación del 77 y 98 por ciento, respectivamente. Con respecto al CE, éste es mayor en forma absoluta en los varones que en las damas. Sin embargo, se mantiene alrededor del 4 por ciento, en todos los grupos. El TE se mantiene entre 3,6 y 3,8 kgs. Estos resultados confieren correlaciones óptimas y errores estadísticamente poco significativos, lo que nos entrega un método de CC confiable de ser usado dentro de los programas deportivos de alto rendimiento nacional

Knee-joint proprioception during 30-day 6 degrees head-down bed rest with isotonic and isokinetic exercise training.

To determine if daily isotonic exercise or isokinetic exercise training coupled with daily leg proprioceptive training, would influence leg proprioceptive tracking responses during bed rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a no-exercise (NOE) training control group (n = 5), and isotonic exercise (ITE, n = 7) and isokinetic exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min periods.d-1, 5 d.week-1. Only the IKE group performed proprioceptive training using a new isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pre-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p < 0.05) at the end of BR in both exercise groups when compared with NOE responses (extension: NOE 80.7 +/- 0.7%, ITE 82.9* +/- 0.6%, IKE 86.5* +/- 0.7%; flexion: NOE 77.6 +/- 1.5%, ITE 80.0 +/- 0.8% (NS), IKE 83.6* +/- 0.8%). Although proprioceptive tracking was unchanged during BR with NOE, both isotonic exercise training (without additional proprioceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.