This core, under the direction of Dympna Gallagher, EdD, provides body composition and physical performance measurements for the Obesity Research Center.
Objectives of the core
| Level Component | Method |
|---|---|
| Atomic Total Body K (TBK) | Measurement of TBK by means of 40K counting in a 4 pi whole body liquid scintillation counter (Pierson et al. 1984; He et al. 2003). |
| Regional (Arm) K | Measurement of segmental body potassium using a ?-ray spectroscopy counting of 40K in a compact newly constructed counter consisting of 4 rectangular NaI (Tl) detectors (Ramirez et al. 2003) |
| Molecular Total Body Water (TBW) | Estimation of TBW by means of deuterium (Yu et al, 1996). |
| Extracellular Water (ECW) | Estimation of ECW by means of radiosulfate or radiobromide dilution (Pierson et al. 1982; Kim et al. 1999). |
| Total Body Fat | Determination using hydrostatic weighing, air plethysmography (Ginde et al. 2005), dual-energy x-ray absorptiometry (Sopher et al. 2004; Soriano et al. 2004); water dilution (Silva et al. 2005); 3-D Photonic Scanner (Wang J et al. FASEB J 19; A48, 2005). |
| Tissue-System Imaging analysis for the following body tissues and organs: Total body/regional Adipose Tissue (AT) Subcutaneous (SAT) Visceral (VAT) Intermuscular (IMAT) Skeletal Muscle(SM) Visceral Organs | VAT (Park et al, 2001; Hoffman et al. 2005); IMAT (Song et al. 2004; Gallagher et al, 2005); SM (Kim et al, 2002; Song et al. 2004)Visceral organs (Hsu et al, 2003; Wang ZM et al. 2005a) |
| Whole-Body | Anthropometry (Wang J et al, 2003; Wang J et al, 2004) single (Pietrobelli et al. 2004a) and multiple (Pietrobelli et al. 2002) frequencies BIA. |
| Evaluation Category | Test Description |
|---|---|
| Endurance/Aerobic Capacity Maximal Exercise Testing | Determination of maximal aerobic capacity by measurement of maximal oxygen consumption measured during a multistage, graded, electrocardiographically monitored exercise test on the treadmill or cycle ergometer with measurement of associated variables: heart rate, blood pressure, and rating of perceived exertion at each work rate. Supervised by Lynn Allen, MD. |
| Prediction of Aerobic Capacity | Estimation of maximal aerobic capacity from submaximal exercise testing in cases where maximal exercise testing is unwarranted or unnecessary. Measurement of VO2, heart rate, blood pressure, and rating of perceived exertion during submaximal exercise. |
| Submaximal Exercise Tests | Determination of submaximal aerobic fitness by means of a submaximal multistage exercise test on a treadmill or cycle ergometer to estimate the anaerobic threshold: I) by assessment of the highest work rate before occurrence of a marked increase in plasma lactate (in collaboration with the Hormone and Metabolite Core); ii) by assessment of the highest work rate prior to a sharp nonlinear rise in minute ventilation relative to VO2, which is produced by the simulation of ventilation by non-metabolic CO2 derived from buffering of lactate. The anaerobic threshold is a well-established index of aerobic fitness. |
| Energy Cost of Physical Activities | Indirect calorimetry with control and monitoring of exercise on: a) a treadmill (Quinton Medtrack ST or Trackmaster TMX425C) with an adjustable speed ranging from 1.5 to 15 mph; adjustable elevation ranging from a 0 to 40o grade; or b) a Monark cycle ergometer (model 818E) with an adjustable external resistance ranging from 0 - 7 kp. This permits measurement of energy cost of both weight-bearing and weight-supported activities. |
| Anaerobic Power | Determination of anaerobic power by use of the Wingate test performed on a cycle ergometer. |
| Efficiency | Determination of muscular efficiency by assessment of the increases in energy expenditure required to meet increases in external work on the cycle ergometer. |
| Strength: Handgrip Strength | Isometric strength, defined as a maximal voluntary contraction, can be achieved between 0.3 and at the most 3.0 seconds using an adjustable handle cable tensiometer (Pacific Scientific, Anaheim, CA). Strength is expressed in kilograms force. Measuring range is from 0 to 100kg. |
| Back and Leg Strength | Isometric strength can be achieved between 0.3 and at the most 3.0 seconds using an adjustable handle cable tensiometer and a footstand (Takei Scientific, Tokyo, Japan). Strength is expressed in kilograms force. Measuring range is from 0 to 300kg. |
| One Repetition Maximum Strength Test (1-RM) | Isotonic muscle strength for chest, shoulder, back, arms, and legs is measured using the 1-RM test. This procedure requires the subject to lift weights in a progressive manner beginning at a low level and gradually reaching the maximal amount of weight that can be lifted at one time, using the appropriate muscle group. Two minute rest periods occur between 1-RM attempts. To minimize injury, a 5-10 minute bicycle warm-up combined with very low intensity weight lifting for each specific muscle group precedes the 1-RM test. A multi-station gym apparatus (Tuff Stuff, Task Enterprises, Pomona, CA) is available for the performance of these tests. |
| Training: Resistance Training | A multi-station gym apparatus (Tuff Stuff, Task Enterprises, Pomona, CA) is available for use in studies that require resistance exercise intervention. The major muscle groups that can be trained include pectorals, triceps, biceps, latissimus dorsi, quadriceps, and hamstrings. Hand held dumbells (5, 10, 15, 20 lb) are also available for biceps curl and triceps kickback exercises. |
| Additional Functional Tests: Endurance, Physical Performance, and Balance | Our laboratory uses a performance battery developed by the Health, Aging, and Body Changes Study, which includes tests of both lower and upper extremity function (e.g. chair stands, standing balance, and timed walk). |
| Six-minute Walk TestStanding Balance Tests | The six minute walking test provides a useful and reproducible measure of exercise tolerance. Furthermore, it is considered a simple practical indicator of everyday disability. |
| Balance Walks | The lower extremity measures, (particularly the tandem stand and semi-tandem stand) provide indicators of balance. These, along with the Tinetti Falls Efficacy scale, serve as indicators of balance. The performance tests allow ratings of the extent to which subjects can hold challenging standing positions. The Falls Efficacy scale assesses respondents' subjective sense of balance in terms of fear of falling and confidence in performing daily activities that put the subjects at risk for falls. |
| The Chair Stand | Two sets of colored lines are placed along an eight foot path/corridor. The green lines are 20 centimeters apart and the orange lines are 30 centimeters apart. The subject is asked to a) walk the path length at a comfortable pace ignoring the colored lines, b) walk the path length keeping feet inside the orange lines, and c) walk the path length keeping feet inside the green lines. Each walk is timed and number of steps recorded from when 'start' to 'finish' lines are crossed. If a subject is unable to stay within designated lines, the test is repeated for a total of three trials. A straight-backed chair is placed next to a wall; participants are asked to stand up from the chair while their arms are folded across their chest. Subjects are asked to stand up and sit down five times as quickly as possible. Timing of this entire session encompasses the initial sitting position to final standing position at the end of the fifth stand. |
Quality control procedures are carried out for each test as presented below (abbreviations defined at bottom of table).
| Core | TEST | Quality Control Procedure(s) |
|---|---|---|
| HBC | Body weight | Linear calibrations and check every 3 months by Bioengineering Department |
| Air plethysmography | Daily standardization with calibrated standard volume cylinders | |
| Bioimpedance analysis | Daily calibration with standard resistors and capacitors | |
| Dual-energy x-ray absorptiometry | Calibration standards run prior to each study as a means of establishing CV's | |
| 40K whole-body counting | Daily calibration with reference KCl phantoms; In vivo 42K calibration for body size | |
| Spirometry | Daily calibration of gas analyzers with standardized gases; Volume calibration with a reference 3 liter syringe. | |
| Energy expenditure | Daily calibration using standardized gases; absolute ethanol burning protocols | |
| Underwater weighing | Load cells tested daily with standard weights | |
| Anthropometry | Steel calibration blocks for caliper; extensive technician training and periodic evaluation | |
| PhysP | Dynamometry measurements | Bioengineering Department calibrations at prescribed intervals |
Abbreviations: HBC, Human Body Composition; PhysP, Physical Performance.
For more information on the Body Composition Unit go to: http://www.nyorc.org/bcu/index.html.
For a list of publications from the Body Composition Core 2000-2005, click here.