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1 52 Journal of Exercise Physiologyonline October 2017 Volume 20 Number 5 Editor-in-Chief Official Research Journal of the Tommy American Boone, Society PhD, of MBA Exercise Review Board Physiologists Todd Astorino, PhD Julien Baker, ISSN PhD Steve Brock, PhD Lance Dalleck, PhD Eric Goulet, PhD Robert Gotshall, PhD Alexander Hutchison, PhD M. Knight-Maloney, PhD Len Kravitz, PhD James Laskin, PhD Yit Aun Lim, PhD Lonnie Lowery, PhD Derek Marks, PhD Cristine Mermier, PhD Robert Robergs, PhD Chantal Vella, PhD Dale Wagner, PhD Frank Wyatt, PhD Ben Zhou, PhD Official Research Journal of the American Society of Exercise Physiologists ISSN JEPonline Physiological Demands of Wheelchair Basketball Poliana Piovezana dos Santos 1, Gislaine Cristina de Souza 2, Danilo Leonel Alves 2, André Luiz Felix Rodacki 2, Adriano Eduardo Lima-Silva 3, Fernando Roberto De-Oliveira 4 1 Department of Physical Education, Lutheran University Center of Ji-Paraná, Rondônia, Brazil, 2 Department of Physical Education, Federal University of Paraná, Paraná, Brazil, 3 Department of Physical Education, Technological Federal University of Paraná, Paraná, Brazil, 4 Department of Physical Education, Federal University of Lavras, Minas Gerais, Brazil ABSTRACT Piovezana P, Souza GC, Alves DL, Rodacki ALF, Lima-Silva AE, De-Oliveira FR. Physiological Demands of Wheelchair Basketball. JEPonline 2017;20(5): This study quantified the time expended with each exercise intensity domain during an official wheelchair basketball (WB) match. Ten male WB players (30.5 ± 7.9 yrs) participated in an adapted incremental field test for the determination of heart rate (HR), and first and second lactate threshold (LT 1 and LT 2, respectively). After, the athletes played official matches with continuous monitoring of HR, in which was determined the time expended during each exercise intensity domain (moderate, heavy, and severe) from HR in the LT 1 and LT 2. No significant differences between the three exercise intensity domains were found when time was expressed in absolute and relative values (P>0.05). The velocity at LL 1 was positively associated with the relative time expended during the moderate exercise intensity, but inversely associated with the heavy domain. In conclusion, time expended in moderate, heavy, and severe exercise intensities is similar (~33%). But, athletes with better aerobic conditioning are able to remain a longer time at moderate exercise intensity, while athletes with poor aerobic conditioning spend more time at the heavy exercise intensity. Key Words: Heart Rate, Intensity Domains, Paralympic Sports, Lactate

2 53 INTRODUCTION Wheelchair basketball (WB) is a paralympic sport for individuals with permanent physical disabilities in the lower body. The main physical characteristics related to WB performance include resistance, strength, speed, coordination, and mobility (8). In particular, aerobic fitness is also important because a typical match lasts around 65 min (3). The determination of lactate thresholds is a widely used tool for the evaluation of aerobic fitness (11). The first and second lactate threshold (LT 1 and LT 2, respectively) can separate aerobic exercise in three different exercise intensities domains: moderate, heavy, and severe (6). By monitoring blood lactate during a match, it is possible to establish the time expended in each of the exercise intensity domains (10,12), which can then be used to improve the athletes training prescription. Measuring blood lactate during a WB match is difficult, given that it adds operational complexity to determine time expended in each exercise intensity domain. An alternative is the measurement of heart rate (HR). It has been widely used to monitor athletes during a WB match (7). Studies have shown that the average HR during a match is between 132 and 151 beats min -1 (3,13). However, it is still unknown as to what is the length of time in each exercise intensity domain during an official WB match. This is important because the quantification of the internal load to which the athletes are submitted during a WB match will help in understanding their physiological needs during the training sessions. Therefore, the purpose of this study was to quantify the time expended during each exercise intensity domain (moderate, heavy, and severe from HR in the LT 1 and LT 2 ) of an official WB match. METHODS Subjects Ten male WB players (age: 30.5 ± 7.9 yrs; training experience: 3.2 ± 3.7 yrs) who competed in regional championship games were the subjects in this study. They were classified according to the International Wheelchair Basketball Federation (IWBF) for level of disability (Table 1). To be part of the study, the subjects: (a) had to have competed in the regional WB championship; and (b) could not have heart disease, hypertension, and/or use of medications that would alter HR. All subjects signed the consent form in accordance with the parameters proposed by the Declaration of Helsinki (5). The Ethics Committee of the Federal University of Santa Catarina approved the study. Procedures The subjects were submitted to an incremental field test adapted for WB (18). Blood samples were taken at the end of each stage of the test for later determination of LT 1 and LT 2. HR was monitored throughout the test. At 7 and 15 days later, the athletes played official matches in the regional championship with continuous monitoring of HR. Both incremental field test and match were carried out at same time of the day. The subjects were advised to avoid engaging in vigorous activities and consuming alcohol and caffeine 24 hrs prior to the evaluations. Also, it was recommended that the subjects eat their last meal at least 2 hrs before the tests. After this time, only water was allowed.

3 54 Table 1. Descriptive Data of the Wheelchair Basketball Players. Player Age (yrs) Injury IWBF Classification 1 43 Viral disease (polio) Spinal cord injuryt Spinal cord injury T Spinal cord injury T Viral disease (polio) Viral disease (polio) Viral disease (polio) Amputation Amputation Amputation 4.5 IWBF = International Wheelchair Basketball Federation Adapted Incremental Field Test The athletes performed the incremental field test in their own match-chairs (18). These chairs were made of standard material and built for each athlete, weighing ~15 kg. The tests were carried out in a gym with wood floor (temperature: 25.4 ± 2.2ºC; relative humidity: 62.6 ± 14.2%). The athletes were instructed to move between two cones 20 m apart, in a shuttle schedule, with velocity controlled by sonorous beeps via software (Sphera Portable Server Software ). The test started at 4.0 km h -1 with increments of 0.5 km h -1 each minute. Pauses of 30 sec were performed every two stages for blood sample collection from the earlobe (25 μl of arterialized blood). The test was interrupted when the subjects were unable to maintain the imposed rhythm, with three successive delays of approximately 1 m of the target cone. HR was recorded every 5 sec throughout the test (Polar model S810i). Blood samples were analyzed immediately after collection for measuring blood [La] (Yellow Springs Instruments, lactimeter model 1500 Sport). Peak HR and blood [La] (HRpeak and [La]peak) were identified at the end of the test. Peak of velocity (PV) was identified as the maximal velocity reached during the test, which was corrected by the time expended in the last incomplete stage (9). Lactate Threshold The [La] measurements were plotted against the corresponding velocity. Values for the stages in which blood samples were not taken were estimated by linear interpolation of the two adjacent stages. A three straight lines fitting was calculated by linear regression with two initially unknown intercepts calculated from every possible intersection between the time

4 points. The first and second intercepts that best shared the curve in three linear segments were considered as LL 1 and LL 2, respectively (14,15). The respective velocities and HR were estimated by linear interpolation. 55 Time Expended Into Each Exercise Intensity Domains during the Match Two athletes had their HR monitored per match by using a HR monitor (Polar model S810i). The HR versus time data were analyzed and time expended in moderate (HR values below LL 1 ), heavy (HR values between LL 1 and LL 2 ), and severe domains (HR values above LL 2 ) were determined. Time expended in each exercise intensity domain was expressed in absolute (min) and relative (%) to the total match time. The HRpeak, HR average, and HR minimum were also recorded, but only the periods in which the athlete was on the court. Statistical Analyses The data normality was tested using the Shapiro-Wilk test. Because there was no normal distribution, the ANOVA of Friedman followed by Wilcoxon test was used to compare the time expended across the three exercise intensities. The possible relation between the time expended at a given exercise intensity domain and the thresholds was identified using the Spearman-Rank correlation. Statistical significance was set at an alpha level of P<0.05. RESULTS The athletes reached 175 ± 12 beats min -1 of HRpeak, 10.4 ± 0.8 km h -1 of PV, and 9.1 ± 2.2 mmol L -1 of [La]peak. The identified LL 1 and LL 2 are reported in Table 2. Table 2. Absolute and Relative Values of the Velocity and HR in the Lactate Thresholds in Adapted Incremental Test for Wheelchair Basketball. Velocity (km h -1 ) PV (%) HR (beats min -1 ) HRpeak (%) LL ± ± ± ± 5.4 LL ± ± ± ± 7.0 PV = Peak Velocity; HR = Heart Rate; HRpeak = Heart Rate Peak; LL 1 = First Lactate Threshold; LL 2 = Second Lactate Threshold The HRpeak was 180 ± 16 beats min -1, the average HR was 163 ± 21 beats min -1, and minimum HR was 91 ± 13 beats min -1 during the matches. No significant differences between the three exercise intensity domains were found when time was expressed in absolute (χ 2 (2) = , P>0.05) and relative values (χ 2 (2) = , P>0.05) (Figure 1). The velocity at LL 1 was positively associated with the relative time expended during the moderate exercise intensity, but inversely associated with the relative time expended during the heavy domain (Table 3). There was no significant correlations between absolute time at a given exercise intensity and the thresholds.

5 56 Figure 1. Time Expended into Each Exercise Intensity Domains during the Match in Absolute (A) and Relative (B) Values. Table 3. Correlations between Relative Permanence Time in Each Match Intensity Domain and the Lactate Thresholds Velocity. Time Moderate Heavy Severe min % min % min % Velocity (km h -1 ) LL * * LL LL 1 = First Lactate Threshold; LL 2 = Second Lactate Threshold; min = Minutes. *Significant correlation (P<0.05). DISCUSSION The main findings of the present study were: (a) the athletes expended a similar time across the three exercise intensity domains during a WB match (~33% in each exercise intensity); and (b) the relative but not absolute time expended at moderate and heavy exercise intensity domains was associated with the velocity at LL 1. The HR at LT 1 and LT 2 was 111 ± 8 and 148 ± 16 beats min -1, respectively. The values for LT 2 was similar to those found by Croft et al. (4), who identified a HR value at LT 2 of 148 ± 4

6 beats min -1, although the HR at LL 1 (130 ± 12 beats min -1 ) and HRpeak (194 ± 9 beats min -1 ) were higher than in the present study. The [La]peak in the present study was close to a previous study that identified [La]peak in a specific treadmill test for WB (10.2 ± 2.1 mmol L -1 ) (8). During a high-level WB match, the average HR is typically in the range of 132 to 151 beats min -1 (3,13). In the present study, the average HR of the subjects was higher (163 ± 21 beats min -1 ). This finding is probably due to the physical fitness of the athletes. The regional level athletes fitness is typically lower than the athletes fitness at the international level (3,13) that demands a high cardiovascular response. Interestingly, Zamunér et al. (19) reported that WB athletes present a lower average resting and exercise HR due to the increase in the level of training and competition (19). It has been established that the WB athletes have metabolic demands similar to basketball for able athletes, with high-intensity movements interspaced with pauses (20). In the present study, there was no difference in time maintained at the moderate, heavy, and severe exercise intensity domains during an official WB match. This is the first study to show that disable athletes demonstrated a similar time in each of the three exercise intensity domains during an official match. However, the time expended in each exercise intensity was independent of the athlete's aerobic conditioning (2,16). For example, while the velocity at LL 1 was positively related to the relative time spent in the moderate exercise domain, it was inversely related to the relative time in the heavy exercise domain. These findings suggest that athletes with better the aerobic conditioning spent more time in the lesser-demanding zone, while athletes with the worse aerobic conditioning spent more time in the more intense zone. Thus, this is means the less trained athletes will experience a greater physiological stress during the match (2). This is consistent with the interpretation that the physiological transition thresholds may assist in predicting performance in sports teams such as WB, which has the characteristic of performing repeated sprints with time spent in different training zones (1). Limitation of the Study It is worth noting that the present study presents some limitations. The athletes had a variety of lesion levels and deficiencies (17), which per se might affect the time spent in each exercise intensity domain. However, it is important to point out that even with this limitation, the results should help assist the coaches in understanding the physiological demands that WB requires and to develop the training prescription accordingly. CONCLUSIONS Time spent in moderate, heavy, and severe exercise intensities is similar (~33%). But, while athletes with a higher aerobic conditioning are able to perform for a longer period of time at moderate exercise intensity, the poorly conditioned athletes will spend more time engaged in heavy exercise intensity. 57

7 58 Address for correspondence: Gislaine Cristina de Souza, Department of Physical Education of Federal University of Parana, Parana, Brazil. Street Sagrado Coração de Jesus, Phone (55) , REFERENCES 1. Bishop D, Girard O, Mendez-Villanueva A. Repeated-sprint ability -- Part II. Sports Med. 2011;41: Bogdanis GC, Nevill ME, Boobis LH, Lakomy H. Contribution of phosphocreatine and aerobic metabolism to energy supply during repeated sprint exercise. J Appl Physiol. 1996;80: Coutts K. Heart rates of participants in wheelchair sports. Spinal Cord. 1988;26: Croft L, Dybrus S, Lenton J, Goosey-Tolfrey V. A comparison of the physiological demands of wheelchair basketball and wheelchair tennis. Inter J Sports Physiol Perform. 2010;5: Declaration of Helsinki. World Medical Association Declaration of Helsinki: Ethical principles for medical research involving human subjects. JAMA. 2013;310: Faude O, Kindermann W, Meyer T. Lactate threshold concepts: How valid are they? Sports Med. 2009;39: Iturricastillo A, Granados C, Yanci J. The intensity and match load comparison between high spinal cord injury and non-spinal cord injury wheelchair basketball players: A case report. Spinal Cord Ser Cases. 2016;2. 8. Knechtle B, Köpfli W. Treadmill exercise testing with increasing inclination as exercise protocol for wheelchair athletes. Spinal Cord. 2001;39: Kuipers H, Verstappen F, Keizer H, Geurten P, Van Kranenburg G. Variability of aerobic performance in the laboratory and its physiologic correlates. Inter J Sports Med. 2985;6: Lucía A, Hoyos J, PÉrez M, Chicharro JL. Heart rate and performance parameters in elite cyclists: A longitudinal study. Med Sci Sports Exer. 2000;32: Midgley AW, McNaughton LR, Jones AM. Training to enhance the physiological determinants of long-distance running performance. Sports Med. 2007:37: Padilla S, Mujika I, Orbananos J, Angulo F. Exercise intensity during competition time trials in professional road cycling. Med Sci Sports Exer. 2000;32:

8 13. Perez J, Rabadan M, Pacheco J, Sampedro J. Heart rate assessment during wheelchair basketball competition: Its relationship with functional classification and specific training design. Sport Pers With Disabil Perspect. 2007; Ribeiro J, Yang J, Adams R, Kuca B, Knutten H. Effect of different incremental exercise protocols on the determination of lactate and ventilatory thresholds. Brazilian J Medical Biolog Res. 1985;19: Ribeiro JP, Hughes V, Fielding RA, Holden W, Evans W, Knuttgen HG. Metabolic and ventilatory responses to steady state exercise relative to lactate thresholds. Europ J Appl Physiol Occupat Physiol. 1986;55: Spencer M, Bishop D, Dawson B, Goodman C. Physiological and metabolic responses of repeated-sprint activities. Sports Med. 2005;35: Vanlandewijck YC, Evaggelinou C, Daly DD, Van Houtte S, Verellen J, Aspeslagh V, Hendrickx R, Piessens T, Zwakhoven B. Proportionality in wheelchair basketball classification. Adapt Phys Activ Q. 2003;20: Vinet A, Le Gallais D, Bouges S, Bernard P, Poulain M, Varray A, Micallef J. Prediction of VO 2 peak in wheelchair-dependent athletes from the adapted Leger and Boucher test. Spinal Cord. 2002;40: Zamunér AR, Silva E, Teodori RM, Catai AM, Moreno MA. Autonomic modulation of heart rate in paraplegic wheelchair basketball players: Linear and nonlinear analysis. J Sports Sci. 2013;31: Ziv G, Lidor R. Physical attributes, physiological characteristics, on-court performances and nutritional strategies of female and male basketball players. Sports Med. 2009;39: Disclaimer The opinions expressed in JEPonline are those of the authors and are not attributable to JEPonline, the editorial staff or the ASEP organization.