The Effect of Depth Jumps and Weight Training on Leg Strength and Vertical Jump

Abstract

In recent years, a method of plyometrics (exercises that cause a rapid lengthening of a muscle prior to contraction) called depth jumping has become a part of the training routine of many athletes. Two experiments are described in which the effectiveness of the exercises is examined. In Experiment 1, undergraduate students in beginning weight training classes trained with three different jumping programs: (1) maximum vertical jumps, (2) 0.3 m depth jumps, and (3) 0.75 m and 1.10 m depth jumps. In addition, all groups also lifted weights. In Experiment 2, a weight training class and the volleyball team at Brigham Young University-Hawaii were divided into two groups. One group lifted weights and performed 0.75 and 1.10 m depth jumps. The other group only lifted weights. In Experiment 1, the three training programs resulted in increases in one repetition maximum (1 RM) squat strength, isometric knee extension strength, and in vertical jump; however, there were no significant differences between treatments. In Experiment 2, all groups made significant increases in vertical jump, except the group of weight lifters, who did no jumping. It was concluded that depth jumps are effective but not more effective than a regular jumping routine.     

The effects of an increasing versus constant crank rate on peak physiological responses during incremental arm crank ergometry

Abstract

We examined the effects of concomitant increases in crank rate and power output on incremental arm crank ergometry. Ten healthy males undertook three incremental upper body exercise tests to volitional exhaustion. The first test determined peak minute power. The subsequent tests involved arm cranking at an initial workload of 40% peak minute power with further increases of 10% peak minute power every 2 min. One involved a constant crank rate of 70 rev · min^?1, the other an initial crank rate of 50 rev · min^?1 increasing by 10 rev · min^?1 every 2 min. Fingertip capillary blood samples were analysed for blood lactate at rest and exhaustion. Local (working muscles) and cardiorespiratory ratings of perceived exertion (RPE) were recorded at the end of each exercise stage. Heart rate and expired gas were monitored continuously. No differences were observed in peak physiological responses or peak minute power achieved during either protocol. Blood lactate concentration tended to be greater for the constant crank rate protocol (P = 0.06). Test duration was shorter for the increasing than for the constant crank rate protocol. The relationship between local RPE and heart rate differed between tests. The results of this study show that increasing cadence during incremental arm crank ergometry provides a valid assessment of peak responses over a shorter duration but alters the heart rate–local RPE relationship.     

The Physiologic Response of Exercising in the Water and on Land with and without the X1000 Walk 'N Tone Exercise Belt

Abstract

Study of the physiological effects of exercise that decreases lower joint impact is needed. Participants (N = 18) were exposed to either land or water exercise that included or did not include wearing a belt. Physiological variables of caloric expenditure, net oxygen cost, net oxygen pulse, and heart rate were assessed A 2 × 2 (Environment × Belt) analysis of variance (ANOVA) revealed a significant environment main effect for net oxygen cost and caloric expenditure. Water actually decreased the energy cost of the exercise. A 2 × 2 × 4 (Environment x Belt x Time) ANOVA revealed a significant environment main effect for net oxygen cost and caloric expenditure. Specifically, land heart rates increased over time, whereas water heart rates did not.     

The effect of crank rate strategy on peak aerobic power and peak physiological responses during arm crank ergometry

Abstract

The main aim of this study was to determine whether the use of an imposed or freely chosen crank rate would influence submaximal and peak physiological responses during arm crank ergometry. Fifteen physically active men participated in the study. Their mean age, height, and body mass were 25.9 (s = 6.2) years, 1.80 (s = 0.10) m, and 78.4 (s = 6.1) kg, respectively. The participants performed two incremental peak oxygen consumption ([Vdot]O_2peak) tests using an electronically braked ergometer. One test was performed using an imposed crank rate of 80 rev · min^?1, whereas in the other the participants used spontaneously chosen crank rates. The order in which the tests were performed was randomized, and they were separated by at least 2 days. Respiratory data were collected using an on-line gas analysis system, and fingertip capillary blood samples (～20 μl) were collected for the determination of blood lactate concentration. Heart rate was also recorded throughout the tests. Time to exhaustion was measured and peak aerobic power calculated. Submaximal data were analysed using separate two-way repeated-measures analyses of variance, while differences in peak values were analysed using separate paired t-tests. Variations in spontaneously chosen crank rate were assessed using a one-way analysis of variance with repeated measures. Agreement between the crank rate strategies for the assessment of peak values was examined by calculating intra-class correlation coefficients (ICC) and 95% limits of agreement (95% LoA). While considerable between-participant variations in spontaneously chosen crank rate were observed, the mean value was not different (P > 0.05) from the imposed crank rate of 80 rev · min^?1 at any point. No differences (P > 0.05) were observed for submaximal data between crank strategies. Furthermore, mean peak minute power [158 (s = 20) vs. 158 (s = 18) W], time to exhaustion [739 (s = 118) vs. 727 (s = 111) s], and [Vdot]O_2peak[3.09 (s = 0.38) vs. 3.04 (s = 0.34) l · min^?1] were similar for the imposed and spontaneously chosen crank rates, respectively. However, the agreement for the assessment of [Vdot]O_2peak (ICC = 0.78; 95% LoA = 0.04 ± 0.50 l · min^?1) between the cranking strategies was considered unacceptable. Our results suggest that either an imposed or spontaneously chosen crank rate strategy can be used to examine physiological responses during arm crank ergometry, although it is recommended that the two crank strategies should not be used interchangeably.     

Effectiveness of Physical Activity Interventions for Preschoolers: A Meta-Analysis

Purpose: The purpose of the meta-analysis was to examine the effectiveness of physical activity interventions on physical activity participation among preschoolers. A secondary purpose was to investigate the influence of several possible moderator variables (e.g., intervention length, location, leadership, type) on moderate-to-vigorous physical activity (MVPA). Method: Nine databases were systematically searched for physical activity interventions. Studies were included if they contained statistics necessary to compute an effect size (ES), were written in or translated into English, examined physical activity in preschoolers, incorporated a physical activity intervention, and targeted preschool-aged children. Fifteen studies satisfied these criteria. ESs were calculated using a random-effects model. Results: Results indicated that overall, interventions had a small-to-moderate effect on general physical activity (Hedges g = 0.44, p < .05, n = 73 ESs) and a moderate effect on MVPA (Hedges g = 0.51, p < .05, n = 39 ESs). The greatest effects for MVPA were identified for interventions that were less than 4 weeks in duration, were offered in an early-learning environment, were led by teachers, involved outdoor activity, and incorporated unstructured activity. Conclusions: This meta-analysis provides an overview and synthesis of physical activity interventions and highlights effective strategies for future interventions aimed at increasing physical activity levels among preschoolers.     

Books reviews

Coaching Children in Sport: Principles and Practice. M. Lee (ed.), E. & F.N. Spon, London, 1993. xiv + 311 pp., £16.99 (pb), ISBN 0 419 18250 0.

Clinical Sports Medicine. P. Brukner and K. Khan, McGraw‐Hill, Sydney, 1993. 697 pp., £48.00 (hb), ISBN 0 07 452852 1.

The Physiology of Sport and Exercise. J.H. Wilmore and D.L. Costill, Human Kinetics, Champaign, IL, 1994. x + 549 pp., £40.00 (hb), ISBN 0 87322 693 3.

Neuromechanical Basis of Kinesiology, 2nd Edn. R.M. Enoka, Human Kinetics, Champaign, IL, 1994. xiii + 466 pp., £40.00 (hb), ISBN 0 87322 665 8.     

Projecting the visual: British newsreels,soccer and popular culture 1918–39

Between the wars soccer was the leading national sport in Britain. But far more watched the brief depictions of ‘celluloid’ soccer on the newsreels in the cinema than ever watched football on the pitch. Newsreels were a central cultural feature, yet their broader social, historical and ideological significance has been overlooked by both sports and media historians. This study draws on an extensive body of surviving newsreel material. It begins by exploring the complex nature of the inter-war cinema audiences, their responses to sporting newsreels and the cultural competencies they brought to their watching. Examination of newsreel content reveals the changing nature and highly varied coverage of professional and amateur soccer over the period, including significant attention devoted to women's soccer even after its banning from English Football Association grounds in 1921. The day to day practices of newsreel soccer coverage provide fascinating insights into the British sporting values and identities, contained, encouraged or prevented by its representations, codes and conventions. Soccer newsreels produced by the leading companies, while largely conservative in tone, were also highly ideologically charged. Through the ways in which they addressed notions of class, gender, politics, region and identity they had a major cultural impact on broader British society.     

Book reviews

Paul Goldman, Sporting Life: An Anthology of British Sporting Prints. (London, British Museum Publications, 1983). Pp. 136. £7.95.

Donald J. Mrozek, Sport and American Mentality, 1880–1910. (Knoxville, University of Tennessee Press, 1983). Pp.xx + 284. NP.

Christopher Dodd, The Oxford and Cambridge Boat Race. (London, Stanley Paul, 1983). Pp.405. £14.95.

Ian T. Henderson and David I. Stirk, The Compleat Golfer: An Illustrated History of the Royal and Ancient Game. (London: Victor Gollancz, 1982). Pp.96. £5.95.

Jean‐Marie Brohm, Sport—A Prison of Measured Time. Essays. (Translated by Ian Fraser). (London: Ink Links, 1978). Pp. ix+ 185. NP.

Robert J. Higgs, Sports: A Reference Guide. (Westport, CT: Greenwood Press, 1982). Pp.317. NP.

Gary Firth, James Hagerty, Keith Laybourn (eds.), Yorkshire at Play: A Guide to Historical Sources and their Uses. (Leeds: University of Leeds School of Education, 1982). Pp.x + 54. NP.

Sir Walter Gilbey, Sport in the Olden Time. (Liss, Hants: Spur Publications Company, 1975). Pp.[xi] + 117. £7.50.

Capt. L. Fitz‐Barnard, Fighting Sports. (Hindhead, Surrey: Triplegate Ltd. (Learnex), 1983). Pp.viii + 292. £15.00.

David B. Smith, Curling: An Illustrated History. (Edinburgh: John Donald Publishers, 1981). Pp.vii + 232. £12.00.     

Securing the Sports ‘Miracle’: The Stasi and East German Elite Sport

Given the political and social importance of East Germany's elite sports system, the Ministry of State Security (Stasi) constructed a comprehensive and invasive system of surveillance to protect the clandestine state doping programme, to prevent flight to the West by sportspeople, to ensure the smooth running of sports events, and in general to help maintain the country's status as a sporting superpower. While the Stasi enjoyed much success in its mission, thanks in no small part to the deployment of several thousand informers, its authority and capabilities were constrained by the magnitude of its many other security operations, the autonomous actions of sports fans and performers, the defection of high-profile individuals, and internecine rivalries between major sport-political and bureaucratic organisations such as the DTSB and the Dynamo Sports Associations. The collapse of the East German communist system and the declassification of state and Party materials opened up both the top-performance sports system and the Stasi to critical enquiry, triggered bitter disputes over the appropriateness of the judicial, moral and political reckoning with East Germany's sporting legacy, and highlighted the convergent paths of elite sport across the Iron Curtain.