Abstract:
:Throughout a beat swinging motion prior to a kip the gymnast changes the relative orientation of his legs and head-torso with respect to his arms. It was observed that if these changes occurred in a correct order he could rapidly increase his swing with his limited strength. If changes in orientation of the body parts did not take place in a correct phase, the person would immediately begin to lose any height gained. Previous measurements of the filmed motion of a gymnast performing this motion and his anthropometric dimension and were used to compute from the Dempster-Hanavan model the gymnast's center-of-mass (CM) and polar moment-of-inertia (I) at each instant throughout the maneuver. A simple mechanical model should be able to reproduce the time history of the CM. This model provides some insight into what might be required to increase one's swing. From filmed motion of "good" and "bad" beat swings leading to a kip and this simple model a simple strategy was devised. Graphs are presented which show that the simple strategy is related to the gymnast's radius-of-gyration. The simple strategy is only for the swinging motion. It was concluded that the strategy of the final, small segment of the kip was not the same as that during the swinging segment but a complex one of largely utilizing the accumulated angular momentum.
journal_name
Med Sci Sports Exercjournal_title
Medicine and science in sports and exerciseauthors
Boykin WH,Breskman Dsubject
Has Abstractpub_date
1980-04-01 00:00:00pages
32-6issue
1eissn
0195-9131issn
1530-0315journal_volume
12pub_type
杂志文章abstract:PURPOSE:Supplementation with inorganic nitrate has been suggested to be an ergogenic aid for athletes as nitric oxide donor. The purpose of this study was to determine whether ingestion of inorganic sodium nitrate benefits well-trained athletes performing a 40-min exercise test in laboratory conditions. In addition, we...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,随机对照试验
doi:10.1249/MSS.0b013e3182687e5c
更新日期:2012-12-01 00:00:00
abstract::The purpose of this experiment was to determine whether reflexive, or more broadly, automatic hamstrings excitation could be elicited during isometric, maximum effort, step increases in knee extension torque. Eight healthy subjects without lower extremity dysfunction or injury performed maximum effort isometric knee e...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1992-10-01 00:00:00
abstract:PURPOSE:Methicillin-resistant Staphylococcus aureus (MRSA) has been recognized as a serious skin infection in the athletic population. Literature in reference to football players has been sparse. We sought to better elucidate circumstances surrounding such infections in collegiate football players. METHODS:Data from t...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,评审
doi:10.1249/MSS.0b013e31816f1534
更新日期:2008-08-01 00:00:00
abstract::To study the physiological responses to walking with hand-held weights (HWs), 12 untrained men completed three sub-maximal and two maximal treadmill tests. Heart rate, oxygen uptake, respiratory exchange ratio, ventilation, systolic blood pressure (BP), diastolic BP, rate pressure product, and rating of perceived exer...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1987-06-01 00:00:00
abstract:PURPOSE:Physical activity questionnaires (PAQs) are considered the most cost-efficient method to estimate total energy expenditure (TEE) in epidemiological studies. However, relatively few PAQs have been validated using doubly labeled water (DLW) in women or in samples with diverse ethnic backgrounds. This study was co...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章
doi:10.1097/00005768-200111000-00024
更新日期:2001-11-01 00:00:00
abstract:PURPOSE:This study determined the effects of a single session of heavy-resistance exercise on myosin heavy-chain (MHC) mRNA expression, along with the expression of the transcription factors Myo-D, myogenin, and Id-1. METHODS:Four male subjects participated in a control group (CON) and seven in a resistance-exercise g...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200208000-00006
更新日期:2002-08-01 00:00:00
abstract:PURPOSE:The aim of this study was to assess the feasibility and the effects of a long-term training program with endurance and strength elements for patients with advanced congestive heart failure (CHF). METHODS:We studied 14 patients, mean age 57 yr, mean NYHA class 2.7, mean LVEF 29%, and mean VO2max 17.2 mL x kg(-1...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199908000-00004
更新日期:1999-08-01 00:00:00
abstract:PURPOSE:For most people, the benefits of physical activity far outweigh the risks. Research has suggested that exercise preparticipation questionnaires might refer an unwarranted number of adults for medical evaluation before exercise initiation, creating a potential barrier to adoption. The new American College of Spo...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000001331
更新日期:2017-10-01 00:00:00
abstract::Recent research has demonstrated that intracellular signaling components associated with several proinflammatory cytokines have the potential to interact with signaling pathways that regulate anabolic processes in skeletal muscle. This presentation and the ensuing brief review are intended to present a selection of th...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e3181b07d12
更新日期:2010-01-01 00:00:00
abstract::Estimates of muscular efficiency in competitive and recreational cyclists at similar work intensities and cycling frequencies were examined. Twelve healthy college-age male nonsmoker volunteers were grouped as either competitive (CC; N = 6) or recreational (RC; N = 6) cyclists based upon previous cycling experience. S...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章
doi:10.1097/00005768-199611000-00008
更新日期:1996-11-01 00:00:00
abstract::Low-intensity exercise (less than or equal to 50% VO2max) has been demonstrated to produce heat acclimation (HA) in trained subjects. The purpose of this study was to determine whether shorter-duration, moderate-intensity exercise would also result in HA. Nine trained runners performed two 9-d exercise heat-stress pro...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/00005768-199010000-00012
更新日期:1990-10-01 00:00:00
abstract:PURPOSE:Increased serum testosterone (TST) occurs in response to resistance exercise and is associated with increased muscle mass. However, the effects of elevated TST and sequential resistance exercise bouts on androgen receptor (AR) expression in humans are not well known. This study examined three sequential bouts o...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1249/01.mss.0000139795.83030.d1
更新日期:2004-09-01 00:00:00
abstract:INTRODUCTION:We examined the relationships between insulin-like growth factor I (IGF-I), its binding protein (IGFBP-3), body composition, and bone mineral density (BMD) in collegiate runners (N = 13), gymnasts (N = 10), and noncompetitive women (N = 10). METHODS:Subjects were evaluated by dual-energy x-ray absorptiome...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200011000-00013
更新日期:2000-11-01 00:00:00
abstract::Machine learning classification models for accelerometer data are potentially more accurate methods to measure physical activity in young children than traditional cut point methods. However, existing algorithms have been trained on laboratory-based activity trials, and their performance has not been investigated unde...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000002221
更新日期:2020-05-01 00:00:00
abstract:INTRODUCTION:Competitive female athletes restrict energy intake and increase exercise energy expenditure frequently resulting in ovarian suppression. The purpose of this study was to determine the impact of ovarian suppression and energy deficit on swimming performance (400-m swim velocity). METHODS:Menstrual status w...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e3182a32b72
更新日期:2014-01-01 00:00:00
abstract:PURPOSE:To test our hypothesis that differences in urinary calcium excretion among blacks and whites may be secondary to ethnic variations in acid (H(+)) metabolism and to prove that increases in titratable acid excretion would be found among individuals predisposed to the development of stress fractures. METHODS:We a...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章
doi:10.1097/00005768-200202000-00018
更新日期:2002-02-01 00:00:00
abstract::In this study the gross efficiency of swimming was determined in a group of male (N = 6) and female (N = 4) competitive swimmers. The gross efficiency is defined as the ratio of the power output (W) to the power input (W). In a range of swimming velocities (0.95-1.6 m.s-1), the power input (rate of energy expenditure,...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1990-06-01 00:00:00
abstract::The objective of this study was to investigate the effects of shoes and foot orthotics on running economy and selected frontal plane knee kinematics during the support phase of running. Twenty-one male runners who had been fitted with orthotics served as subjects. Subjects participated in three submaximal runs on a tr...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1985-02-01 00:00:00
abstract:PURPOSE:This study investigated the effects of the menstrual cycle on prolonged exercise performance both in temperate (20°C, 45% relative humidity) and hot, humid (32°C, 60% relative humidity) conditions. METHODS:For each environmental condition, 12 recreationally active females were tested during the early follicula...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e3182656f13
更新日期:2012-11-01 00:00:00
abstract:INTRODUCTION/PURPOSE:To examine whether fluctuations in training load during an Olympic year lead to changes in bone mineral densities and factors that regulate bone (sclerostin, osteoprotegerin and receptor activator of nuclear factor kappa-B ligand), energy metabolism (insulin-like growth factor-1 and leptin), and in...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000001640
更新日期:2018-09-01 00:00:00
abstract:PURPOSE:It is unclear how muscle strength in tibial rotation and knee abduction change following anterior cruciate ligament (ACL) injury and reconstruction. Such strength changes are likely, considering the oblique orientation of the ACL and the constraint provided by the ACL at various tibial rotation and adduction po...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章
doi:10.1097/00005768-200201000-00002
更新日期:2002-01-01 00:00:00
abstract:UNLABELLED:Ratings of perceived exertion (RPE) were developed to provide a subjective estimation of exercise intensity during exercise but are also used to produce exercise intensities and to report the intensity of completed exercise sessions. PURPOSE:To determine the relationship between RPE assessed before, during,...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e31818a0f09
更新日期:2009-03-01 00:00:00
abstract::The gravity-dependency and age-dependency of noradrenergic vasoconstrictor outflow to skeletal muscle (muscle sympathetic nerve activity; MSNA) in humans was analyzed by applying microneurography technique. The basal level of MSNA in the horizontally supine position increased with aging without significant changes in ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199610000-00039
更新日期:1996-10-01 00:00:00
abstract:PURPOSE:The effect of exercise on body mass is likely to be partially mediated through changes in appetite control. However, no studies have examined the effect of chronic exercise on obestatin and cholecystokinin (CCK) plasma concentrations or the sensitivity to detect differences in preload energy in obese individual...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,随机对照试验
doi:10.1249/MSS.0b013e31827d1618
更新日期:2013-05-01 00:00:00
abstract:PURPOSE AND METHODS:It is commonly recognized that there is familial aggregation for physical activity level. However, the genes and sequence variants responsible for the familial clustering have not been investigated. We performed a genome-wide linkage scan based on 432 markers typed in 767 subjects from 207 families ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/01.MSS.0000078937.22939.7E
更新日期:2003-08-01 00:00:00
abstract:PURPOSE:This study aimed to test whether incident kidney cancer risk is associated with exercise energy expenditure (i.e., metabolic equivalents, 1 MET) when calculated from distance walked or run. METHODS:Hazard ratios (HR) and 95% confidence intervals (95% CI) from Cox proportional hazard analyses of self-reported p...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e3182a4e89c
更新日期:2014-02-01 00:00:00
abstract::Equations are often used to predict cardiorespiratory fitness (CRF) from submaximal or maximal exercise tests. However, no study has comprehensively compared these exercise-based equations with directly measured CRF using data from a single, large cohort. PURPOSE:This study aimed to compare the accuracy of exercise-b...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000002435
更新日期:2021-01-01 00:00:00
abstract::During the past three to four decades, a significant amount of data was collected to reinforce the notion that mitochondrial function is irrevocably linked to mitochondrial structure. Indeed, data from numerous studies have revealed several salient points of mitochondrial biology that include the following: 1). mitoch...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,评审
doi:10.1097/00005768-200301000-00014
更新日期:2003-01-01 00:00:00
abstract::Ten eumenorrheic nonathletic women, aged 21-25, were studied on the 8th day following the LH peak in three consecutive cycles. Plasma level and metabolic clearance rate (MCR) of estradiol (E2) and progesterone (P) were measured before and during a 2-h continuous treadmill test at a speed corresponding to 70% of their ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1992-07-01 00:00:00
abstract:PURPOSE:To develop a protocol for isolating changes in aerodynamic and rolling resistances from field-based measures of power and velocity during level bicycling. METHODS:We assessed the effect of body position (hands on brake hoods vs drops) and tire pressure changes (414 vs 828 kPa) on aerodynamic and rolling resist...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e3181fcb140
更新日期:2011-05-01 00:00:00