Communications to the Fourth Annual Congress of the European ...

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PART III: HUMAN PERFORMANCE Published online: 07 Feb 2011.

To cite this article: (2000) PART III: HUMAN PERFORMANCE, Journal of Sports Sciences, 18:7, 499-508, DOI: 10.1080/02640410050078454 To link to this article: http://dx.doi.org/10.1080/02640410050078454

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499

Conference communications the grip strength test. When the ® ngers are taped, the climber cannot produce as much force as when the ® ngers are not taped. It is suggested that this is a result of the tape pushing the tendon into the osseo-aponeuroses and, therefore, changing the vector through which the force is applied. As the force generated by the ® ngers is less, the strain which the A2 pulley is under is reduced. Therefore, taping of the ® ngers could reduce the risk of injury to the A2 pulley.

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PART III: HUMAN PERFORMANCE Eþ ects of time of day and warm-up on a cycling time trial G. Atkinson, C. Todd, T.P. Reilly and J.M. Waterhouse Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, UK

Atkinson et al. (1994: Journal of Sports Sciences, 12, 127± 128) reported that the race times of competitive cyclists, aged 20± 30 years, vary with time of day, with worse performances being recorded in the morning. These results could be due to the stiþ ness and lower body temperature reported soon after waking from sleep and the fact that the morning is not a young athlete’ s usual time of training. Such external in¯ uences would be expected to be reduced if `morning type’ athletes are examined after performing a prolonged warm-up before the morning test of performance. Our aim was to determine whether diurnal variation in cycling performance is still present in such circumstances. Eight male cyclists (age = 24.9 ± 3.5 years, peak power output (PPO) = 357 ± 38 W; mean ± s) completed four test conditions, each separated by at least 72 h and administered in a counterbalanced order; participants tested after a 5 min (`short’ ) self-selected warm-up at 07:30 and 17:30 h, respectively, and participants tested after a 25 min warm-up performed at 60% PPO at 07:30 and 17:30 h, respectively. The mean chronotype score on a 13± 55 scale was 39 ± 6, which places all participants in the upper morningness quartile for a normative young adult population that was also administered the questionnaire (n = 87, mean = 30 ± 6). In each condition, participants performed a 16.1 km time trial (Atkinson et al., 1999: Journal of Sports Sciences, 17, 18) on a `Kingcycle’ ergometer (Palmer et al., 1996: International Journal of Sports Medicine, 17, 293± 298). Participants woke at about 06:00 h on all experimental days. Heart rate, intra-aural temperature and perceived exertion (RPE) were measured throughout the time trial and mean responses to the exercise were calculated for each participant. Post-test blood lactate concentration was also recorded. The mean (± s) performance time was 1415 ± 100 s in the morning tests and 1366 ± 93 s in the afternoon (P = 0.0002). The mean time after the long warm-up was 15 ± 18 s faster than after a short warm-up (P = 0.05). There was no interaction between the in¯ uence of warm-up duration and time of day on performance times (P = 0.3). The long warm-up in the morning increased the mean intra-aural temperature from 35.7 ± 0.5°C at rest to 36.5 ± 0.4°C just before the time trial (P = 0.001). This was higher than the pre-time trial mean

temperature of 36.1 ± 0.4°C recorded after the short warm-up in the morning (P = 0.05), but not signi® cantly diþ erent (P = 0.2) from the pre-time trial temperature of 36.7 ± 0.5°C recorded in the afternoon with a long warm-up. No eþ ect of warm-up was found on the intra-aural temperature responses to the time trial itself (P = 0.9), which were, nevertheless, aþ ected by time of day (P = 0.002). The mean post-test lactate concentration was 9.4 ± 0.6 mmol ´l- 1 in the morning and 11.4 ± 1.8 mmol ´l- 1 in the afternoon (P = 0.02). No eþ ects (P > 0.1) of time of day or warm-up duration were found for heart rate and RPE. These results contrast with those of Dalton et al. (1997: International Journal of Sports Medicine, 18, 538± 542) and suggest that cycling performance is worse in the morning than in the afternoon, even with `morning type’ athletes who woke at least 90 min before the test and performed a vigorous 25 min pre-test warm-up. This warm-up was suý cient to raise pre-test body temperature to values similar to those recorded in the afternoon, but body temperature during the time trial and lactate after the time trial were still lower in the morning. This suggests that pre-exercise body temperatures do not fully explain the diurnal variation in performance and some physiological responses to self-selected exercise.

Eþ ect of exercise duration on optimal pedalling rate in well-trained triathletes J. Brisswalter 1 and C. Hausswirth2 1

Department of Applied Physiology and Health Factors, LAPMH, University of Poitiers and 2Department of Sport Sciences, INSEP, Paris, France

A classical approach of locomotion is based on the notion that biological systems are coordinated such that optimal performance is achieved at least cost (e.g. Wilkie, 1977: International Journal of Neurosciences, 7, 125± 143). However, with this approach the nature of cost must be identi® ed. It is therefore unlikely that metabolic cost is always the criterion of minimum eþ ort. Within this framework, observations of expert cyclists often reveal a signi® cant diþ erence between their preferred and most economical cadences (e.g. Gregor et al., 1991: Exercise and Science Reviews, 9, 127± 168). Several assumptions have been made to explain this apparent con¯ ict, such as changes in pedalling forces and neuromuscular activation. In fact, optimization principles governing locomotion for cycling are probably as numerous as for other forms of locomotion, and thus the adoption of a speci® c locomotor pattern could be seen as a function of (a) the task constraints and (b) the constraints of the performer (Holt et al., 1996: Journal of Motor Behaviour, 27, 164± 178). The aim of this study was to examine whether the speci® c physiological changes observed during prolonged endurance cycling exercise could be related to a speci® c relation between optimal and freely chosen cadence in a homogeneous group of triathletes. Ten well-motivated individuals selected on the basis of their performance over the Òlympic distance triathlon’ participated in the study. Each participant completed two test cycling track sessions in a 2-week period. During both

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Conference communications


Ç O2) and iEMG values of the vastus lateralis muscle associated with the 4 controlled and the freely chosen cadences Table 1. Oxygen uptake (V (FCC) in cycling 65

80

95

110

FCC

VÇ O2 (ml ´kg- 1 ´min- 1)

Period 1 Period 2

53.4 ± 6.4 57.9 ± 8.5

52.3 ± 7.0 55.7 ± 7.4

54.7 ± 4.2 59.3 ± 7.1

59.1 ± 4.9 64.1 ± 7.0

54.0 ± 7.5 58.6 ± 8.6

iEMG (UA)

Period 1 Period 2

36.2 ± 3.8 38.2 ± 4.0

29.1 ± 3.1 28.5 ± 2.7

26.0 ± 2.4 26.2 ± 3.4

33.1 ± 3.4 32.2 ± 3.1

26.5 ± 2.1 26.5 ± 2.1

tests, respiratory gases were collected using the Cosmed K4 telemetric system, which has previously been validated (Hausswirth et al., 1997: International Journal of Sports Medicine, 18, 449± 453). The ® rst session was used to determine VÇ O2m ax and HRm ax . The second session was conducted at 75% HRm ax . It was composed of ® ve submaximal treadmill rides (lasting 5 min), corresponding to ® ve cadences presented in random order (65, 80, 95, 110 rev ´min- 1 and freely chosen cadence, FCC), before and after a 1 h cycling track ride. During the submaximal rides, respiratory gas exchange, heart rate, cadence and speed were collected continuously and energy cost of locomotion was calculated. Furthermore, during this test, EMG signal of the vastus lateralis muscle was recorded. Results indicate a slight shift in energetically optimal cadence with exercise duration from an optimal zone (65± 80 rev ´min- 1) to an optimal point (80 rev ´min- 1). This result con® rms a precedent study conducted at 80% VÇ O2m a x during a 30 min ride (Brisswalter et al., 1999: International Journal of Sports Medicine, in press). No eþ ect of duration was found for iEMG values. Despite a small decrease at the end of the test, no signi® cant eþ ect of duration was found on freely chosen cadence (FCC). During the ® rst period, the freely chosen cadence (90 ± 10 rev ´min- 1) was closed from the iEMG optimum of the vastus lateralis muscle, whereas during the second period (82 ± 8 rev ´min- 1), it was closed only from the energy cost optimum (Table 1). These results suggest that the change of working muscle activity pattern could be related to the increase in VÇ O2 with time for all pedal rates, or to the shift in energetically optimal rate towards a higher pedal rate at the end of the exercise. In this study, the preferred cadence represents the most economical choice adopted during a 1 h ride performed at the usual training pace for triathletes.

Is regular physical activity adequate to improve maximal strength in the elderly? J. Carvalho,1 J. Cabri,2 J. Oliveira,1 J. Magalh° es1 and J.M.C. Soares1 1

Department of Sport Biology, Faculty of Sport Sciences, University of Porto and 2Faculty of Human Motricity, Lisbon, Portugal

Age-related decrease in muscle strength is well described in the literature. Several cross-sectional studies have shown that isometric and isokinetic muscle strength of the quadriceps in older men and women is lower than in younger individuals. Furthermore, it is well known that strength training can attenuate this decline. Most of these studies were based on speci® c strength exercises and not on general physical activity programmes. The purpose of this study was to determine the eþ ects of a 6-month general physical activity programme on quadriceps and hamstring strength in persons over 65 years. Initial (baseline), intermediate (after 3 months) and ® nal (after 6 months) measurements of maximal strength of the quadriceps and hamstrings were carried out on an isokinetic dynamometer (Biodex, System 2, USA) at 1.05 and 3.14 rad ´s- 1 in 32 elderly volunteers (12 men, 20 women; age 69.4 ± 4.1 years, height 157 ± 8 cm, body mass 69.8 ± 14.4 kg; mean ± s). All were independent in their daily activities, without any clinically relevant diseases and with no signs of morbidity for at least 2 years prior to the study. The physical activity performed was based on general exercises (aerobic conditioning, general strength, coordination and ¯ exibility), performed two times per week, each session lasting 1 h. Before testing, the participants performed a standardized warm-up on a bicycle (Monark, Sweden) for at least 5 min, using a resistance of 2% of body mass. Furthermore, they were accustomed to the dynamometer through a submaximal

Table 1. Peak torque (N ´m) at the three instants of evaluation 3.14 rad ´s-

1.05 rad ´s-

1

Extension

Baseline 3 months 6 months

Flexion

1

Extension

Flexion

D

ND

D

ND

D

ND

D

ND

58.8 ± 16.8 57.9 ± 16.8 58.1 ± 16.1

52.0 ± 16.0 52.3 ± 14.6 53.6 ± 15.4

30.9 ± 9.6 34.0 ± 12.4 33.1 ± 10.3

31.5 ± 9.4 32.2 ± 11.1 30.2 ± 9.1

91.9 ± 24.7 88.7 ± 25.8 89.8 ± 24.4

84.9 ± 28.0 85.8 ± 25.5 84.9 ± 24.9

42.2 ± 13.8 42.3 ± 16.3 41.9 ± 15.7

41.4 ± 12.3 40.8 ± 14.8 39.2 ± 11.8

D = dominant leg, ND = non-dominant leg.

501

Conference communications Table 2. Quadriceps/hamstrings ratio (%) 3.14 rad ´s-

Baseline 3 months 6 months

1.05 rad ´s-

1

1

D

ND

D

ND

46.7 ± 10.3 47.8 ± 8.9 47.2 ± 10.4

48.5 ± 9.4 48.9 ± 12.2 47.4 ± 11.2

53.8 ± 13.7 58.5 ± 12.8 57.0 ± 10.8

62.9 ± 18.1 63.3 ± 18.2 58.1 ± 15.9


D = dominant leg, ND = non-dominant leg.

isokinetic exercise protocol. The sequence of the maximal strength test was: dominant leg 5 knee extension/¯ exion repetitions at 3.14 rad ´s- 1, 2 min rest, 3 repetitions at 1.05 rad ´s- 1, followed by the same routine in the non-dominant leg. Statistical analysis (repeated-measures ANOVA) revealed no signi® cant (P > 0.05) changes between the baseline, 3 months and 6 months measurements. The results are presented in Tables 1 and 2. Training twice a week for 1 h over 6 months seems insuf® cient to induce marked changes in isokinetic strength of the elderly. The low-intensity, non-speci® c strength exercises and the low frequency of exercises for muscular training might explain the lack of signi® cant alterations in strength. These results suggest that a non-speci® c strength programme is not an adequate stimulus to increase strength in older people.

Energy demands in elite water polo players participating in games of diþ erent duration N. Geladas and Th. Platanou Faculty of Physical Education and Sport Science, University of Athens, Greece

Water polo is a physically demanding game (Pinnington et al., 1988: Journal of Human Movement Studies, 15, 101± 108) played over four periods, each lasting 7 or 9 min, depending on the speci® c rules applied by the local or international water polo authorities. The present study was designed to explore

the prevailing exercise intensity in 20 exhibition games, half of which lasted 28 min (4 periods ´ 7 min each, SG), whereas the other half terminated after 36 min of play (4 periods ´ 9 min each, LG). In addition, we also tested the hypothesis that the playing position and standard of the player aþ ect energy systems diþ erently. Before the games, 15 members of the First Division Clubs (FD) and 15 National Team members (NT) were evaluated on basic physical and physiological parameters related to performance. All physiological variables were tested in the water (Table 1). Subsequently, throughout all games, heart rate (HR) was monitored continuously, while at the end of each period capillary blood samples were taken and lactate concentration (LA) was determined. The mean overall HR during the SG and LG conditions, for all players (n = 30), was 156 ± 18 and 157 ± 18 beats ´min- 1, respectively, values which were almost equal to the predetermined heart rate at the anaerobic threshold (155 ± 12 beats ´min- 1) and which corresponded to a blood lactate concentration of 4.03 ± 0.96 mmol ´l- 1. Post-exercise mean blood lactate concentration during SG and LG was 3.8 ± 1.22 and 3.91 ± 1.89 mmol ´l- 1, respectively. Regardless of the duration of the game, there was a signi® cant (P < 0.001) decrease in HR (from 158 to 153 beats ´min- 1) and blood lactate concentration (P < 0.003) (4.02 to 3.47 mmol ´l- 1) between the ® rst and last game period. In addition, we found that the HR of LG was consistently lower by 4 beats ´min- 1 (156 vs 152) (P < 0.001) during the last 6 min of the game compared to the SG condition. Whereas during the games no diþ erences were observed in the exercise intensity attained in the various playing positions, the First Division players’ inferior aerobic system (Table 1) was taxed to a greater extent when compared with National Team members, judging from the higher mean HR (P < 0.001) and blood lactate concentration (P < 0.002) values they exhibited. We conclude that playing water polo successfully requires a high anaerobic threshold at an intensity of which all the game should be performed, because based on the results of the elite players examined in the present study, it appears that the exercise intensity drifts to lower levels as the game proceeds. This becomes even more imperative in games lasting not 28 but 36 min.

Table 1. Physical and physiological characteristics of elite Greek water polo players (n = 30)

Age (years) Height (cm) Body mass (kg) Somatotype (pure) 400 m (min:s) VÇ O2ma x (ml ´kg- 1 ´min- 1) LAm a x (mmol ´l- 1) HRm a x (beats ´min- 1) HRAT (beats ´min- 1)

First Division

National Team

P

22.45 ± 3.31 183 ± 5 88.27 ± 10.01 3.51± 5.23± 1.74 5:08 ± 0:22 57.14 ± 9.26 10.83 ± 2.78 191 ± 7 163 ± 10

22.57 ± 3.57 182 ± 5 82.11 ± 8.14 2.61± 5.03± 2.26 4:48 ± 0:11 70.23 ± 6.97 8.97 ± 1.87 181 ± 7 147 ± 10

n.s. n.s. n.s. 0.008 0.008 0.001 0.05 0.001 0.001

Total 22.51 ± 3.38 183 ± 5 85.19 ± 9.82 3.06± 5.13± 1.98 4:58 ± 0:22 63.69 ± 10.44 9.90 ± 2.51 186 ± 9 155 ± 12

Note: 400 m = performance time during free swimming, HRAT = heart rate at the anaerobic threshold. P-values are comparisons between First Division and National Team members. Diþ erences in somatotype derive only from the endomorphy component.

502 An assessment of children’s habitual physical activity in relation to diþ erent activity criteria N. Gilson,1 C. Cooke2 and C. Mahoney3 1


Sport and Health Department, Liverpool Hope University College, 2 School of Leisure and Sports Studies, Leeds Metropolitan University and 3 Department of Sports Studies, Roehampton Institute, London, UK

By applying lifestyle (Children’ s Lifestyle Physical Activity Model, C-LPAM) rather than performance-related (Exercise Prescription Model, EPM) activity criteria, a dramatic increase in activity has been suggested to occur in those children classi® ed as active (Corbin et al., 1994: Physical Activity and Fitness Research Digest, 8, 1± 7). As previous investigations used only one model or compared models in retrospect, the purpose of this study was to document any concurrent changes in children’ s activity volume that may occur through the application of diþ erent activity criteria. Children and adolescents (12 boys: age 15.1 ± 1.4 years, height 173 ± 8 cm, body mass 59.6 ± 13.8 kg, %body fat 16.4 ± 6.3; 13 girls: age 15.4 ± 1.2 years, height 166 ± 7 cm, body mass 54.4 ± 4.1 kg, %body fat 22.8 ± 5.4) had their heart rate (HR) recorded for a minimum of 3 days (2 school days and a day at the weekend) during the same week in autumn. Using ACSM (1990: Medicine and Science in Sports and Exercise, 22, 265± 274) guidelines (light = 35± 59% HRm ax , moderate = 60± 79% HRm a x, vigorous = 80± 89% HRm ax , heavy = 90%+ HRm a x), HR data were analysed in terms of EPM (20 min of sustained moderate-to-vigorous physical activity three times a week) and C-LPAM (energy expenditure of 6± 8 kcal ´kg- 1 ´day- 1 or 42± 56 kcal ´kg- 1 ´ week- 1) criteria. Energy expenditure was estimated from HR data using individual HR± VÇ O2 regression equations. Results indicated that although only nine (36%) individuals achieved the recommended volume of activity prescribed by the EPM, when judged by the C-LPAM 15 (60%) individuals were found to be active (mean energy expenditure of 51.6 ± 29.6 kcal ´kg- 1 ´week- 1). This clearly documents a concurrent change in activity volume with the application of diþ erent criteria. This supports the results of Corbin et al. (1994), who suggested that an increase in children’ s activity volume occurs with the application of C-LPAM criteria. Such increases appear dependent upon changes in intensity and duration. Through the manipulation of EPM data, further analysis revealed that decreases in intensity from moderate+ to light+ activity resulted in a dramatic increase in the number of individuals classi® ed as active (from 9 to 25, increase of 64%). Furthermore, with regard to duration, a decrease from 20 to 10 and 10 to 5 min of moderate, sustained activity resulted in a 16% (4 individuals) and 8% (2 individuals) respective increase in those able to be classi® ed as active. Increases in activity with the application of the C-LPAM may therefore be due to the lower levels of intensity and duration such a model prescribes. Indeed, such diþ erences are evident when contrasting EPM with C-LPAM criteria, in that the EPM is synonymous with high-intensity, sustained activity, whereas the C-LPAM is associated with lower-intensity, accumulated activity.

Conference communications Modelling the in¯ uence of fat-free mass and physical activity on maximum oxygen uptake in older men and women P.J. Johnson,1 D.A. Cunningham,1,2 D.H. Paterson,2 J.J. Koval,2 A.M. Nevill3 and E.M. Winter4 1

De Montfort University Bedford, UK, 2University of Western Ontario, Canada, 3Liverpool John Moores University and 4Sheý eld Hallam University, UK

During the later periods of life, maximum oxygen uptake Ç O2m ax ) declines with advancing age. In concert with this loss (V of aerobic power, fat-free mass (Tzankoþ and Norris, 1977: Journal of Applied Physiology, 43, 1001± 1006) and level of physical activity (Cunningham et al., 1968: Journal of Gerontology, 23, 551± 559) have also been reported to decline. Both fat-free mass (FFM) and physical activity in¯ uence VÇ O2m ax . The purpose of this study was to model the in¯ uence of FFM and physical activity and so derive a meaningful estimation of the age-speci® c decline in VÇ O2m a x in older men and women. Data previously reported by Cunningham et al. (1997: Canadian Journal of Applied Physiology, 22, 439± 453) on a strati® ed random sample of 152 men and 146 women aged 55± 86 years were used in this study. Ethics approval was provided by the University of Western Ontario Ethics Committee. High-intensity physical activity (PA) was estimated using the Minnesota Questionnaire for the Assessment of Leisure Time Physical Activities (Taylor et al., 1978: Journal of Chronic Diseases, 31, 741± 755). The in¯ uence of age and FFM on VÇ O2m ax was investigated using an allometric model proposed by Nevill and Holder (1994: Applied Statistics, 43, 653± 666). Sex, entered as a dummy variable (coded `0’ for women and `1’ for men), and PA, entered as a continuous log-linear variable, were also incorporated. This produced an expression of the form: VÇ O2m a x = FFMb1 ´PAb2 éxp( b0 + b3 áge + b4 ´sex) ´ e The model was linearized by taking the natural logarithm (ln) of VÇ O2m ax , FFM and PA. Parameters were identi® ed using multiple regression. Signi® cance was set at P < 0.05. The sex variable was not signi® cant (P = 0.062) and thus removed from the analysis. The model explained 72.1% (R = 0.849) of the variance in VÇ O2m a x . Individual b-coeý cients (± standard error of the estimate) for FFM (0.971 ± 0.047), PA (0.026 ± 0.008) and age (- 0.015 ± 0.001) were signi® cant (P < 0.01) and were incorporated into the allometric model: VÇ O2m ax = FFM0.971 ´PA0.026 éxp(- 2.48 - 0.015 áge) ´ e The residuals were normally distributed (P = 0.200) and no relationship was found between the absolute residuals and predictors (P > 0.10), con® rming that the error was multiplicative and had been correctly treated by the logarithmic transformation. Age-associated decline in VÇ O2m a x , independent of FFM and PA, was » 15% [0.985 éxp(age)] per decade. Moreover, sex was not signi® cant, indicating that the aerobic power of older men and women is the same and declines at the same rate with advancing years.

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athletes have more strength in the upper limbs, while the coordination of breathing (%Diþ ) is an important parameter only for serious faults of technique. In conclusion, the strength of the upper limbs is important for pentathletes in competitions of swimming, but secondary to the technique of swimming, which remains the key element.

Arm strength of pentathletes in relation to crawl stroke and competition times V. Magini,1 A. Sabatini,1 F. Sardella,2 L. Dapretto1 and D. Maiello1 University Institute of Motor Sciences (IUSM) and 2 Institute of Sport Science, Rome, Italy


1

Modern pentathlon is a complex sport, where it is important to consider the key elements in each discipline. Particularly in swimming, the strength available and the ability to use it are useful parameters to de® ne to improve performance. To establish the relationship between strength and the transfer ability of this in water, 10 Italian national pentathletes (age 25 ± 4 years, height 179 ± 5 cm, body mass 71 ± 6 kg) were tested in water and on land. A swimming-¯ ume was used for the test in water: the athlete was tethered to a straingauge and had to swim to the best of his ability 10 crawl strokes without breathing in apnoea and then he had to repeat the same test including breathing. A computer, connected to the strain-gauge via an A/D interface, memorized and elaborated the results to have the immediate proceeding of strength during swimming. For the dry land test, an isometric dynamometer (MK7) was used to record the strength (F ) of the most important muscles of the arms involved in the crawl stroke. The percentage of strength transferred in water (%FT) and the percentage of strength lost or gained during respiration were calculated (%Diþ ) from the values of strength recorded with the isometric dynamometer and with the tethered swimming. Finally, for every athlete, the average speed of the better natatorial performance of competition (200 ms) of the last 3 months before the test was taken into consideration. In Table 1, the athletes are listed in order according to speed. The athletes with the best speeds are the ones who have a good transfer of strength in water (%FT) (good technique) and, under the same transfer of strength (%FT), the faster

The Loughborough Intermittent Shuttle Test ± a ® eld test which replicates the demands of soccer C.W. Nicholas,1 F.E. Nuttall2 and C. Williams1 1

Human Muscle Metabolism Research Group, Department of Physical Education and Sports Science, Loughborough University and 2 West Bromwich Albion FC, West Midlands, UK

The aims of this study were to describe and determine the test± retest reliability of an exercise protocol designed to simulate the activity pattern characteristic of the game of soccer (the Loughborough Intermittent Shuttle Test, LIST). The LIST protocol consists of two parts. Part A comprises a ® xed period of variable intensity running over 20-m shuttles; Part B consists of continuous running, alternating every 20 Ç O2m ax until volitional fatigue. m between 55% and 95% V Seven trained games players (age 21.5 ± 0.9 years, height 182 ± 2 cm, body mass 80.1 ± 3.6 kg, VÇ O2m ax 59.0 ± 1.9 ml ´kg- 1 ´min- 1; mean ± sxÅ) performed the LIST on two occasions (trial 1 and trial 2), at least 7 days apart, to determine the test± retest reliability of the sprint times and running capacity. The physiological and metabolic responses to the LIST on both occasions were also monitored. The participants ingested water, ad libitum, during the ® rst trial, and were then prescribed the same amount of water during the second trial. Venous blood samples were collected from an antecubital vein at rest, after every 15 min of exercise during Part A, and at the end of the test.

Table 1. Performance results for individual pentathletes

Athletes H F C E B G A D I L Mean s

Isometric strength F (N)

Apnoea strength A (N)

Crawl strength C (N)

Transfer strength (%FT)

Apnoea/ breath. (%Diþ )

Speed (m ´s- 1)

256 339 287 266 225 361 412 322 299 349 311 53

83 36 131 106 100 106 140 111 123 164 110 33

86 33 96 100 102 102 131 119 131 155 106 31

32.48 10.63 45.47 40.09 44.29 29.45 34.04 34.37 41.25 46.94 35.90 10.14

3.38 - 9.01 - 26.31 - 6.04 2.67 - 3.73 - 6.94 7.96 6.66 - 5.41 - 3.68 9.45

1.322 1.415 1.449 1.455 1.464 1.466 1.473 1.516 1.524 1.537 1.462 0.059

r(x, y) 0.3455 0.6319 0.6883

r2 0.1194 0.3993 0.4738

t 1.0415 2.3062 2.6844

P 0.32808 0.04997 0.02773

Correlations: Speed vs isometric strength Speed vs apnoea strength Speed vs crawl strength


504


Fifteen-metre sprint times during trials 1 and 2 averaged 2.42 ± 0.04 s and 2.43 ± 0.04 s, respectively. Run time during Part B was 6.3 ± 2 min for trial 1 and 6.1 ± 1.3 min for trial 2. Limits of agreement of 0.13 s for sprint times and 2.7 min for run times during Part B were observed. No diþ erences between trials were found for heart rate, rating of perceived exertion, post-exercise changes in body mass, or blood lactate and glucose concentrations during the LIST. We conclude that the sprint times and the Part B run times during the LIST were reproducible. In addition, the activity pattern and the physiological and metabolic responses during the LIST closely simulated the demands of soccer. The LIST, therefore, may be a valuable measurement tool in studying the physiological and metabolic responses to intermittent high-intensity exercise.

Repeatability of lifetime exercise data A. Oinonen,1 E. Lev„lahti,1 R. Simonen,1 T. Videman1,2,3 and M.C. Battie3 1

Department of Health Sciences, University of Jyv„ skyl„ , 2The Finnish Twin Cohort Study, University of Helsinki, Finland and 3Department of Physical Therapy, University of Alberta, Canada

Retrospective epidemiological studies are based on recall of past physical activity, yet the repeatability and validity of historical physical loading data is not well established (Pols et al., 1996: Medicine and Science in Sports and Exercise, 28, 1020± 1025; Bernstein et al., 1998: American Journal of Epidemiology, 147, 147± 154). The repeatability of exercise history data has been found to be acceptable, when studied in selected samples of athletes and patients (Barnekow-Bergqvist et al., 1998: Spine, 23, 235± 243; Friendenreich et al., 1998: Medicine and Science in Sports and Exercise, 30, 266± 274). Similar studies have not been conducted of lifetime exercise history data in general population samples. The objective of the present study was to determine the repeatability of lifetime exercise history data gathered through a structured interview. The participants were 150 male monozygotic twins aged 35± 69 years (mean 49 ± 8.5 years) from the populationbased Finnish Twin Cohort. Initial interviews were carried out from 1992 to 1993 and repeated in 1997. The structured interview used to gather information on exercise participation since the age of 12 years used major life events, such as periods

of education, military service and marriage, as reference points to aid memory. Detailed data were collected on type of sport, frequency (times per week), duration (minutes per session) and intensity (light, moderate, strenuous), as well as years and months per year of participation. The mean time between initial and repeat interviews was 4 years and 10 months (range = 1.8 years, s = 0.4). For each of the 150 participants, interviews were repeated for the most commonly noted physical activity from the age of 12, as recorded from the initial interview. The answers for the identical time period from the two interviews were then compared. Of the 150 participants, 10 were inactive men reporting no exercise activities in either interview. Complete exercise history interviews were repeated in a subgroup of 38 participants. The interviewer was blinded to the responses of the initial interview at the time of collecting repeat interview data. Because twin sibling data are not independent, only one twin of each pair was used for calculating Kendall’ s tau and the intra-class correlation coeý cient (ICC) statistics. Analyses were also conducted using the general estimating equations coeý cient, which permitted use of both twin siblings’ data. Overall, the 5-year repeatability of exercise history data for the most commonly performed exercise activities was acceptable for most parameters (Table 1). The repeatability of all lifetime exercise history data among the subgroup of 38 men yielded an ICC of 0.60 (P < 0.01) for average hours per week of lifetime exercise activities, an ICC of 0.78 (P < 0.001) for months per year of exercise activity, an ICC of 0.65 (P < 0.001) for years of exercise activity performed at least once a month, and an ICC of 0.90 (P < 0.001) for the year that the exercise activity was discontinued. In conclusion, a structured interview provides a reasonably repeatable method for gathering detailed lifetime exercise history data.

Rhythm-based training for young football players C. Persichini, S. Demarie, A. Fonte and L. Capranica University Institute of Motor Science (IUSM), Rome, Italy

Rhythmic ability, which implies discrimination of acoustic, visual and kinetic structures and their translation in coordinated motor response, is considered an essential component of sport performance. Football requires high rhythmic ability to produce appropriate responses according to the variability

Table 1. Kendall’ s tau, ICC and general estimating equations coeý cient (GEE) for repeatability of exerciserelated variables Variables Frequency (times per week) Duration (minutes per event) Intensity (1± 3) Months per year of exercise Mean lifetime exercise hours per week Competitive sport (yes/no) Injuries (yes/no) * P < 0.05, ** P < 0.01, *** P < 0.001.

n 71 71 70 64 64 71 69

Tau

ICC

n

GEE

0.44*** 0.76***

139 139 138 128 128 139 137

0.49*** 0.52*** 0.49*** 0.75*** 0.78*** 0.47*** 0.52***

0.43*** 0.78*** 0.75*** 0.67** 0.36*

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Conference communications of open skills (D’ Ottavio and Roticiani, 1990: A Scuola di Calcio. Rome: Edizione Nuova Prhomos). Nonetheless, there is a lack of information regarding the interaction between rhythmic and technical abilities. Thus, the aim of this study was to ascertain the eþ ects of a rhythmic training programme on technical abilities in young football athletes. Twenty-four young football players aged 9± 11 years were randomly divided into an experimental (n = 13) and a control group (n = 11). For 3 months, the same football training programme was administered twice a week to both groups. The experimental group was rhythmically led with a whistle or hand clap by their coach. Before and after the programme, each participant’ s rhythmic ability was evaluated by means of a computerized rhythmic test (Capranica et al., 1995: Communication to the 3rd International EGREPA Conference, Madrid, 6± 10 September), which included three diþ erent rhythmic patterns (R1, R2, R3). To evaluate football technical abilities, two ® eld tests (FT) were administered (D’ Ottavio, 1994: La Prestazione del Giovane Calciatore: Dall’ Avviamento alla Prima specializzazione. Rome: Ed. Junior). In addition to the rhythmic and football scores, the velocity variations (VV) from the correct pattern of the rhythmic test and the velocity of execution (TV) of the technical tests were considered. Diþ erences (P < 0.05) between groups and between preand post-training scores were ascertained by means of the Mann-Whitney U-test. Student’ s t-test was applied to velocity values. Tables 1 and 2 show the descriptive statistics for the studied parameters. Before training, no diþ erence between groups was found for both technical and rhythmic parameters. After training, the experimental group showed better and statistically signi® cant diþ erences for technical and R3 scores. Pre± post training comparisons showed signi® cant improvements for R1 and R2 rhythmic scores of the experimental group only (R1, P = 0.002; R2, P = 0.01). Furthermore, the experi-

mental group were signi® cantly faster in the technical test and showed less velocity variations in the rhythmical test after the training programme (RV1, P = 0.0001; RV2, P = 0.001; RV3, P = 0.008; TV, P = 0.04), while the control group showed no diþ erence. In conclusion, since at the end of the programme the experimental group showed signi® cantly better technical and rhythmic abilities than the control group, rhythmic training proved to be an eþ ective method to improve football technical skills.

Assessment of balance performance in the elderly: A twin study C. Pulejo, M.C. Calcaterra, D. Cherubini, M. Pittaluga and P. Parisi University Institute of Motor Sciences (IUSM), Rome, Italy

One relevant aspect of the ageing process is the reduced ability of the nervous system to help maintain balance. Dizziness and loss of balance are common ailments of the elderly, which greatly increase the risk of falls, reduce independence and quality of life (Martini, 1992: Geriatrics, Italy, 9, 12± 19). Body sway is commonly assessed using force platforms to measure the movement of the centre of foot pressure through electric signals (Figura et al., 1991: Journal of Sports Medicine and Physical Fitness, 31, 235± 242). Balance seems to be positively related both to motor capacity, such as muscular strength of the lower limbs, and to the history of one’ s level of physical activity (Era and Heikkinen, 1985: Journal of Gerontology, 40, 287± 295). Physically active elderly persons perform better than non-physically active ones in many sensorimotor tasks and balance tests, suggesting that an active lifestyle could slow

Table 1. Rhythmic and technical scores for the experimental and control groups (mean ± s) Pre-training Scores R1 R2 R3 FT

Post-training

Experimental

Control

Experimental

Control

10.6 ± 4.9 14.0 ± 10.1 14.3 ± 6.3 4.8 ± 1.0

9.5 ± 7.6 11.1 ± 6.2 16.0 ± 11.8 4.5 ± 0.7

7.2 ± 1.2 8.2 ± 4.4 10.8 ± 4.9 5.1 ± 0.8

10.5 ± 6.8 14.5 ± 13.1 16.6 ± 7.7 4.3 ± 0.7

Table 2. Rhythmic and technical velocities for the experimental and control groups (mean ± s) Pre-training

Post-training

Velocity

Experimental

Control

Experimental

Control

R1 (ms) R2 (ms) R3 (ms) FT (s)

- 178 ± 60 - 133 ± 105 - 188 ± 143 16.4 ± 6.3

- 88 ± 155 - 33 ± 133 - 83 ± 245 17.2 ± 1.1

- 110 ± 68 - 25 ± 60 - 105 ± 85 15.6 ± 6.2

- 55 ± 148 - 110 ± 95 - 43 ± 160 17.2 ± 6.8

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Conference communications Table 1. Results for the two sets of paired twins (mean ± s, with mean percent intra-pair diþ erence in parentheses) Mean sway speed (mm ´s- 1)


Mean radius (mm) MZ (11 pairs)

DZ (10 pairs)

MZ (11 pairs)

DZ (10 pairs)

Romberg Eyes open Eyes closed

6.5 ± 1.4 (15) 7.9 ± 2.2 (22)

6.4 ± 1.6 (33) 7.9 ± 1.5 (28)

21.1 ± 5.9 (15) 35.3 ± 19.3 (34)

22.2 ± 10.5 (28) 32.2 ± 14.7 (37)

Tandem Eyes open Eyes closed

8.7 ± 2.4 (26) 12.1 ± 2.7 (25)

9.2 ± 2.3b (20) 10.6 ± 1.6c (21)

40.0 ± 14.0 (26) 65.0 ± 25.4 (25)

48.9 ± 15.1b (30) 67.0 ± 18.4c (18)

One-foot Eyes open

10.6 ± 2.9a (23)

12.1 ± 1.6c (12)

66.7 ± 17.6a (16)

97.4 ± 23.6c (26)

a

Nine pairs; b eight pairs; c ® ve pairs.

the degenerative ageing process (Lord et al., 1994: Archives of Physical Medicine and Rehabilitation, 75, 648± 652). However, the role of individual diþ erences is still controversial. Genetic studies have been conducted on such variables as body size, physiological ® tness and motor performance (Bouchard and Malina, 1983: Exercise and Sport Sciences Reviews, 11, 306± 339). The aim of this study was to investigate balance abilities in elderly twins to estimate to what extent genetic factors may play a role in their variability. The sample consisted of 11 monozygotic (MZ) and 11 dizygotic (DZ) pairs of male twins aged 67± 78 years (mean = 72.4). The pairs were drawn from the Twin Registry of Rome and studied in the context of a wider collaborative project described in detail elsewhere, including lifestyle assessment with respect to past and current physical activity levels. Balance performance was assessed by three diþ erent tests: Romberg, Tandem (30 s) and one-foot test (15 s) performed with eyes open and closed. All data were obtained using a dynamometric platform. The mean radius (MR) measured (mm) and the mean sway speed (MS) expressed in mm ´s- 1 describe the body sway of the centre of foot pressure (COP). Body sway increased with the increasing diý culty of the balance task, as well as for closed eyes conditions in both groups. The one-foot test proved the most diý cult, since only 25% of participants completed this test and only 7% performed the closed-eyes one. These results are worse than those previously obtained for 62-year-olds, con® rming that age plays a relevant role in balance performance. Intra-pair diþ erences were calculated both for MZ and DZ twins and, on account of the small numbers involved, expressed as absolute mean percent diþ erences of the pairs’ averaged values. MZ twins tend to be more similar than DZ twins in some tests but the results are not consistent. This was con® rmed by intra-pair correlations (in Romberg eyes open test, r-values are 0.66 vs - 0.29 for MR and 0.80 vs - 0.08 for MS respectively in MZ and DZ pairs) and by the reduced number of DZ twins capable of completing all the tests. The negative DZ correlation and some other inconsistencies do not allow conclusions to be drawn, but it appears that genetic eþ ects, if any, are far from clear-cut. On the other hand, the speci® c analysis of ® ve MZ pairs with only one twin having practised sport in the past, while the co-twin was sedentary,

indicates lower correlations, thereby stressing the in¯ uence of past sport activity on balance in the elderly.

Cardiorespiratory demands and estimated energy cost in water polo games F.A. Rodr¡guez and X. Iglesias Institut Nacional d ’Educaci¢ F¡sica de Catalunya, Universitat de Barcelona, Spain

The physiological demands of intermittent sports and games are diý cult to establish, particularly if competition takes place in the water. The purpose of this study was to investigate the cardiorespiratory demands and estimated energy cost of waterpolo, based on post-exercise oxygen uptake and continuous heart rate (HR) measurements during a training game in a group of high-standard players. Seven professional water polo players (Spanish First Division team) participated in the study. They took part in a high-intensity training game (match-play against another First Division team) consisting of four playing periods of 10 min with 3± 4 min of recovery. Heart rate (HR) was monitored continuously (Sport-Tester PE-4000, Polar, Finland). Oxygen uptake was measured `breath by breath’ (CPXII, Medical Graphics, USA) at least twice in every player during each of the four periods (immediately postexercise, during time-outs and at the end of each period). The match was ® lmed for time-action analysis and precise Ç O2 measurements and matching HR. Within recording of V a one-week period, all participants performed a maximal incremental test in an electrically braked cycle ergometer with continuous `breath by breath’ measurements using the same Ç O2 linear function was determined gas analyser. The HR± V for each participant. Finally, direct O2 uptake measurements during the simulated game were compared with the predicted HR± matched VÇ O2 values during the ergometer test. Student’ s paired t-test was used to compare the mean measured and predicted values. A minimal squares regression analysis was also performed, and the Pearson’ s linear correlation coeý cient and the standard error of the estimate were computed.

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Conference communications Ç O2 measured during the game was higher for The average V the ® eld players (n = 6; 2.959 ± 0.337 l ´min- 1) than for the goalkeeper (2.109 ± 0.313 l ´min- 1). In relation to body mass, Ç O2 values were 35.2 ml ´kg- 1 ´min- 1 (n = 6; s = 5.4) the mean V and 29.6 ml ´kg- 1 ´min- 1 (s = 4.4), respectively. That corresponds to an average relative intensity of 70.5% (s = 13.6) of the individual maximal aerobic power determined in the laboratory. The average peak relative values attained during the most intense phases were 93.5% (s = 12.0), ranging from 85 to 114% of laboratory determined VÇ O2m ax . The estimated rate of energy expenditure during the game was calculated as ranging from 35 to 80 kJ ´min- 1 (8± 19 kcal ´min- 1), with a mean of 57.3 kJ ´min- 1 (s = 9.0; n = 7). When regression analysis was applied to the measured and predicted VÇ O2 values, a moderately high correlation was observed (r = 0.78; P < 0.001). However, the estimated values were 208± 521 ml ´min- 1 (CI 95%) lower than the measured ones, corresponding to an average underestimation of 13.7% of the real values. These results clearly illustrate the high aerobic demands and high energy cost of high-standard water polo games. In a previous study, large anaerobic glycolytic requirements were also indicated (blood lactate concentrations from 5.0 to 12.0 mmol ´l- 1 in nine ® eld players), as a consequence of the sustained high-intensity exercise during a real game (Rodr¡guez, 1994: In Medicine and Science in Aquatic Sports, edited by Miyashita et al., pp. 172± 177. Basel: Karger). We conclude that modern water polo places high cardiorespiratory and metabolic (both aerobic and anaerobic) demands on high-standard players.

Adolescence predictors of physical inactivity in adulthood

persons at high risk for inactivity at an early stage. The aim of the present study was to evaluate the eþ ects of physical activity and other relevant factors at the age of 14 years on physical inactivity at the age of 31 years. The study population was based on all 12,000 men and women who were born in northern Finland in 1966 and have been followed up since their birth. The participants were 7656 people who answered a postal inquiry both at the age of 14 and 31 years. At the age of 14, the participants were asked about their participation in sports, marks in physical education and in theoretical subjects, membership in a sport club and social class based on parents’ occupations. At the age of 31, respondents were classi® ed as inactive if they participated in moderately intensive physical activity once a month or less often. The risk for inactivity at the age of 31 years was expressed in terms of crude risk ratios for selected variables recorded at the age of 14 years. Table 1 shows that a low level of physical activity, low scoring in theoretical subjects at school, regular smoking and low social class at the age of 14 were associated with increased risk of inactivity at the age of 31, while membership in a sport club and high marks in physical education were associated with a lower risk. Information on factors predicting physical inactivity among young adults is valuable because it oþ ers a tool for identifying individuals who may experience health hazards in adulthood. The present results suggest that inactive individuals could be identi® ed in adolescence using information on their personal characteristics such as leisure time sport activities, school achievements and possibly lifestyle factors. Poor living conditions in early life (measured here by social class) may also contribute to adoption of unhealthy living habits, which may be diý cult to change in later life.

T. Tammelin,1 H. Rintam„ki,1 S. N„yh„,1 M.-R. J„rvelin2,3 and E. Heikkinen4 1

Oulu Regional Institute of Occupational Health and 2Department of Public Health Science and General Practice, University of Oulu, Finland, 3 Department of Epidemiology and Public Health, Imperial College School of Medicine, London, UK and 4 Department of Health Sciences, University of Jyv„ skyl„ , Finland

Physical inactivity is associated with health risks. To obtain optimal health bene® ts, adequate physical activity should be maintained throughout life. It would be useful to identify

Optimal exchange gain in high-standard 4 100 m sprint relay G. Weingarten and M. Ayalon The Zinman College of Physical Education and Sport Sciences at the Wingate Institute, Israel

This study tested the myth that the optimal time gain is 0.8± 0.9 s per baton exchange in the 4 ´ 100 m sprint relay.

Table 1. Crude risk ratios and their 95% con® dence intervals (CI) for physical inactivity at the age of 31 years by selected variables recorded at the age of 14 years Crude risk ratio (CI) Characteristics at the age of 14 years Participation in sports after school once a week or less often vs twice a week or more often Membership in a sport club (yes/no) High (³ 7) vs low (