Perceptual and Motor Skills, 2003,97, 1150-1162. O Perceptual and Motor Skills 2003
INFLUENCE O F THE TYPE O F TRAINING SPORT PRACTISED O N PSYCHOLOGICAL AND PHYSIOLOGICAL PARAMETERS DURING EXHAUSTING ENDURANCE EXERCISES '" M. GARCIN, L. MILLE-HAMARD, S. DEVILLERS, E. DELATTRE, S. DUFOUR Faculte' des Sciences du Sport et de lJEducation Physique Universite' de Lille 2 V. BILLAT Centre de Me'decine du Sport C.C.A.S., Paris Summary.-The present purpose was to study the influence of the type of training sport practised (long distance running, sprinting, handball) on ratings of perceived exertion (RPE), estimation of time limit (ETL), and heart rate (HR) on running tests. It was hypothesised that these parameters would be related to the type of training sport practised. 3 1 trained women (10 endurance-trained runners, 10 sprinters, and 11 handball players) performed two exercises to exhaustion on an outdoor track. The first test was a graded run to estimate maximal aerobic speed (Sm), i.e., the minimal speed which elicited maximal oxygen uptake. The second test was a constant all-out run at speed delta 50 (SMO),which corresponded to the speed halfway between ShlA and the speed at lactate threshold (SLT),to specify time to exhaustion at this intensity (TLIM).Sensations regarding W E , ETL, and HR were recorded during these tests. Sm, SMO,and SLT, expressed in absolute values (km - hr.-') were statistically significantly different between groups ( p < .05) whereas TLIMwas not. The covariance analysis showed that endurance-trained runners perceived the exercise as lighter and presented lower HR than handball players and sprinters for a same running %Sm ( p < .05). Moreover, endurance-trained runners felt that they could endure more than the other groups at a given %Sm or relative exhaustion time (%TLIM).These results mean that the type of training sport which has been performed may mediate perceptual responses and influence physiological parameters during exhausting exercises. These results are likely in part related to sport-specificity of the exercise mode used in tests. This point must be taken into consideration by physical trainers who have to prescribe exercise intensities during athletic seasons for different groups of athletes.
The establishment of the optimal exercise intensity is an important point in the field of training for performance or rehabilitation. Indeed, overestimation of exertion can lead to injuries, diseases, or an overtraining syndrome (Kuipers & Keiser , 1988; Karvonen , 1992). Consequently, it seems important to pay attention to perceived-exertion to individualise prescription of training exercise intensity and duration. Most studies of perceived exertion 'This study was supported by grants from a Projet Hospitalier de Recherche Clinique (No. 28/1959). Address correspondence to Murielle Garcin, Laboratoire d'Etudes de la Motriciti: Humaine, Faculti. des Sciences du Sport et de 1'Education Physique, Universiti: de Lille 2, 9 rue de l'universitt, 59790 Ronchin, France or e-mail (
[email protected]).
TRAINING SPORT AND RUNNING TESTS
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in relation to physical work have been performed with the Rating of Perceived Exertion scale ( W E , from 6-20), described by G. A. V. Borg in 1970 (Borg & Noble, 1974; Eston, Davies, & Williams, 1987; Robertson & Noble, 1997; American College of Sports Medicine, 1998). The values are recorded during an incremental exercise (estimation phase) and thereafter subjects have to produce an appropriate power output for a preselected RPE value (production phase) (Eston & Williams, 1988). A second perceived exertion scale based on subjective estimation of exhaustion time (Estimation of Time Limit, ETL) has been used in addition to RPE during exercise, to understand further how the subject feels (Garcin, Vandewalle, & Monod, 1999; Garcin & Bdat, 2001). The W E scale concerns the current status of the subject (how hard the exercise is currently perceived to be) whereas the ETL scale deals with a subjective prediction of how long the current exercise rate can be maintained. Many studies have already dealt with the Rating of Perceived Exertion scale in different kinds of exercises or sports: walking, running, cycling, or swimming ( Ekblom & Goldbarg, 1971; Noble, Metz, Pandolf, Bell, Cafarelli, & Sime, 1973; Borg, Van Den Burg, Hassmtn, Kaijser, & Tanaka, 1987; Berry, Weyrich, Robergs, Krause, & Ingalls, 1989; Ljunggren & Hassmtn, 1991; Thomas, Ziogas, Smith, Zhang, & Londeree, 1995). Some of these studies relate differences between activities in terms of perceived exertion (Noble, et al., 1973; Skinner, Hustler, Bergsteinova, & Buskirk, 1973; Borg, et al., 1987; Berry, et al., 1989; Thomas, et al., 1995; Hausswirth, Brisswalter, Vallier, Smith, & Lepers, 2000). W E was higher for bicycling than running (Skinner, et al., 1973; Borg, et al., 1987; Thomas, et al., 1995), and higher for walking than running for walking speed higher than 6.9 km - h r r l and 5.04 km - hr.-' (Noble, et al., 1973; Berry, et al., 1989, respectively). However, others found no difference in perceived exertion across exercise modalities (Ekblom & Goldbarg, 1971; Hetzler , Seip, Boutcher , Pierce, Snead, & Weltman, 1991). Moreover, these exercises across modalities were always performed by the same set of laboratory subjects in each study. To our knowledge, only one study has yet focused on perceived exertion responses for groups of athletes of different specialties during a given exercise, i.e., the effects of the type of training sport practised on perceived exertion (Hassmkn, 1990). Moreover, in the recommendations of the A.C.S.M. (1998), no precision is given for the prescription of exercise intensity by type of training sport practised. Therefore, the purpose of the present study was to examine the influence of the type of training sport practised (long-distance run, spring, handball) on ratings of perceived exertion and estimation of time limit, and heart rate during exhausting runs performed on a track. These exhausting runs are becoming routine in the physiological testing of athletes at the beginning of
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the season (Gore, 2000). It was hypothesised that both psychological and physiological parameters would be related to the type of training sport practised.
METHOD Participants Thirty-one trained women participated. Ten were endurance-trained ll these women runners, 10 were sprinters, and 11 were handball players. A trained between three and five times per week and had practised their respective activity for at least 8 yr. During this time they only practised physical education at school and had not participated in other sports. These athletes were chosen to represent endurance activity (runners), speed (sprinters), and combined (handball players). Descriptive data on all 3 1 women are presented in Table 1. They were medically examined before they signed an informed consent form about the purpose and procedures of the experiment. Approval for testing was obtained from the Comitt Consultatif de Protection des Personnes pour la Recherche Biomtdicale de Ldle. TABLE 1 PHYSICAL CHARACTERISTICS OF SUBJECTS (N = 3 1) Group
n
Age (yr.)
M
SD
Mass (kg)
Stature (cm)
M
M
SD
SD
10 19.3 55.6 1.7 1.8 165.2 3.2 10 19.8 1.1 58.4 4.0 164.8 2.8 11 19.0 0.8 62.0 5.2" 168.4 2.5t "Handball players are significantly heavier than endurance-trained runners ( p < .05). tHandball players are significantly taller than endurance-trained runners and sprinters ( p < .05). Endurance-trained runners Sprinters Handball players
Materials The perception of exertion was studied using two scales, a French translation of the Rating of Perceived Exertion scale (Borg, 1970; Shephard, Vandewalle, Gil, Bouhlel, & Monod, 1992), which consisted of 15 assessments between 6 and 20 (from "very, very light" to "very, very hard") (Table 2a), and a second scale based on subjective Estimation of Time Limit which consisted of 20 assessments between 1: more than 16 hours and 20: 2 minutes (Garcin, et al., 1999; cf. Table 2b). This scale was designed as a function of the logarithm of the estimated exhaustion time [ETL = 21 minus 2n, with n=log2(TLIM)where TLIMwas the exhaustion time expressed in minutes] (Table 2b). Heart rate (HR) was recorded with a cardiotachometer (Accurex+@,Polar, Kempele, Finland). Procedure In a first session, the three groups performed an incremental exhaustion exercise on an outdoor track (400 m) to specify their maximal aerobic speed
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TRAINING SPORT AND RUNNING TESTS TABLE 2 RPE SCALE*AND SCALEBASEDON ESTIMATION OF EXHAUSTION TIME^ (a) How Hard Do You Feel This Exercise Is?
(b) How Long Would You Be Able To Perform An Exercise At This Intensity To Exhaustion?
very, very light
2 minutes
very light
4 minutes
fairly light
8 minutes
somewhat hard
15 minutes
hard
30 minutes
very hard
1 hour
very, very hard
2 hours
4 houurs 8 hours more than 16 hours "Rating of Perceived Exertion scale (Borg, 1970). tEstimation of time limit (Garcin, et al., 1999).
(SMA).SMAwas defined as the minimal speed eliciting the maximal oxygen uptake. According to the performances of these subjects, the initial speed was set at SMA- 6 km . hr.-' for exhaustion to occur for each subject within 20 min. (Demarle, Slawinski, Lafitte, Bocquet , Koralsztein, & Billat, 2001), and increased by 1 km . hr.-' every 3 min. until exhaustion. Each stage was separated by a 30-sec. rest. The speed during the last fully completed stage corresponded to the SMA.Each subject was verbally encouraged to give maximum effort. The speed at the lactate threshold (SLT)was estimated by the relation between blood lactate concentrations and speed. It was defined as the speed for which an increase in lactate concentration corresponding to 1 mmol . L-I occurred between 3 and 5 mmol - L-I (Aunola & Rusko, 1992). Speed delta 50 (SMO),which was the speed halfway between SMAand SLT, was calculated as follows: SMO= SLT+ [(SMA- SLT)/2]. This speed is known to be sustainable for about 10 min. and allows subjects to elicit maximal oxygen uptake at the end of a run (Bdlat, Slawinski, Bocquet, Demarle, Lafitte, Chassaing, & Koralsztein, 2000). Two days later and on the same track the subjects performed a constant run up to exhaustion at SMoto specify the time to exhaustion at this speed (TLIM).Each subject was verbally encouraged to continue for as long as possible.
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Speed was checked during the incremental and the constant exercises by the experimenters. O n the track, the athletes followed a pacing cyclist travelling at the required speed. The cyclist received audio cues via a Walkman (Sony'), the cue rhythm setting the speed needed to cover 25 m. Visual marks were set at 25-m intervals along the track (inside the first lane) (Billat, et al., 2000). Moreover, experimenters independently measured the time required to complete 25 m to check the pacer's and runners' speed. For the graded and the constant-run exercises, exhaustion was defined when the subject was unable to sustain the speed, i.e., when the runner fell more than 5 m behind the cyclist. During exercise, heart rate was recorded every 5 sec. and averaged with the three highest consecutive values during the last 30 sec. of each stage for incremental tests and during the last 30 sec. of every 2-min. period for constant-run tests. Fingertip capillary blood samples were collected in a capillary tube and were analysed for lactate concentration using a Dr LangeB, LP20 (Berlin, Germany). Blood lactate concentration was assessed by enzymatic oxidation analysis. Fingertip blood samples were taken at the end of every stage (during the 30-sec. rest) during the graded exercise. The scales were explained for each subject before each exercise as recommended by Noble, et al. (1973). These scales were written on a board fixed on the back of the experimenter who rode in front of the subject. The subjects were asked "How hard do you feel this exercise is?" and "How long would you be able to perform an exercise at this intensity to exhaustion?" For the incremental exercise, subjects had to give ratings corresponding to their sensations during the last 15 sec. of each stage (estimation phase). They had to point to a value on the perceived exertion scales, and the ratings were collected during the 30-sec. rest. For the constant-run exercise, ratings were expressed every 2 min. to the end of exercise to a second experimenter who rode next to the runner and collected the values. The order of rating perceived exertion and estimation of time limit scales was the same during both exercises for each subject but was randomised among the subjects of each group to balance any effect of order of presentation of the scales on perceptual responses. Analysis Results are presented as means f standard deviations. Statistical differences among groups for the speeds (maximal aerobic speed, speed MO, or speed at the lactate threshold) and time to exhaustion at speed MO were tested with a one-way analysis of variance. Statistically significant differences were identified by Student-Newman-Keuls post hoc test. Moreover, the relationships between pairs of variables were analyzed by a Pearson product-moment test (Sigma stat', Jandel, Germany). Thereafter, a covariance analysis
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was carried out on the relations between parameters to estimate the effect of the type of sport practised on ratings of perceived exertion, estimation of time limit, or heart-rate values during an exhausting test performed at a given percentage of maximal aerobic speed (%SMA)or exhaustion time (%THM) (Hays, 1994). For all analyses, statistical significance was set at p < .05.
RESULTS Maximal aerobic speed, speed A50, and speed at the lactate threshold expressed in absolute values were statistically significantly different between endurance-trained runners, sprinters, and handball players ( p < .05), whereas these speeds expressed in relative values and time to exhaustion at speed MO were not statistically significantly different between groups ( p > .05); cf. Table 3. Mean maximal heart rates (HR max) were not statistically significantly different between groups (197 f7 bpm, 194 f4 bpm, and 196 f6 bpm, for handball players, endurance-trained runners, and sprinters, respectively) ( p < .05). TABLE 3
Endurance-trained Runners
Sprinters
M
SD
Handball Players
M
SD
krn . hr.-I km . hr.-'
16.5 14.3 1.3 13 V . 0.7 1.7" 15.4 13.3 1.1 12.8 0.8 1.8" 2.3 92.9 2.3 92.3 3.0 %SM 93.2 to SLT km . hr.-' 14.3 1.9" 12.3 0.9 11.7 1.1 4.2 84.6 6.0 3.9 86.2 86.8 %Sm TLIM sec. 81 1 208 600 116 610 220 "Endurance-trained runners are significantly different from sprinters and handball players ( p < .05). to SM to S,
Ratings of perceived exertion ( W E ) , estimation of time limit (ETL), and heart-rate values (HR) were statistically significantly correlated with speed expressed as a percentage of maximal aerobic speed (%SMA)( p < .O1; cf. Table 4). The covariance analysis showed a statistically significant upward (F2,180= 17.59, shift of the regressions between W E , ETL, HR, and F,,,,, = 25.63, and F,,,,, = 3.4 1, p < .05, respectively; cf. Fig. la, l b , and lc). This means that for a given relative speed (%ShlA),endurance-trained runners perceived the exercise as lighter, felt that they could endure more, and presented lower mean heart rate than sprinters and handball players. Similarly, the relations between ETL and W E and between ETL and HR were
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TABLE 4 CORRELATION COEFFICIENTS, NUMBER OF VALUES INCLUDED IN EACHRELATIONSHIP, AND CONFIDENCE INTERVALS FORRELATIONS BETWEEN PERCEIVED EXERTION (RPE), ESTIMATION OF TIMELIMIT(ETL), AND PERCENTAGE OF MAXIMAL AEROBIC SPEED(%Sm) OR EXHAUSTION TIME(%TLIM) FORENDURANCE-TRAINED RUNNERS (n = l o ) , SPRINTERS (n = l o ) , AND HANDBALL PLAYERS (n = 11) % S,
Group
WE
ETL
HR
WE
.93 .86 .80 .81 Endurance-trained Runners 64 values 64 values 64 values 58 values .89
