Winter 2007

Sport Science Issue

Winter 2007

The Magazine of the Sport Medicine Council of Alberta

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Latest News from the SMCA…………...Page 3

table of contents

An Examination of Softball Slo-pitch: Effects of Spin on Ball Trajectory

By P. Gervais & T. Wu

Pages: 6 & 7

Investigation of Total, Free and Bound Leptin in Olympic Development Athletes

By PK. Doyle-Baker, A. Venner & ME. Lyon

Pages: 8 & 9 Physiological Characteristics of Female Varsity Rugby Union Players

By A.B. Game & N.D. Eves

Pages: 10 & 11

Evaluation of the Bike Power Saver through 3D Kinematics & EMG Analysis

By G. Shan

Page: 14

2 SMCA Pulse Winter 2007

The Nadir in Serum Glucose as a Predictor of Anaerobic Threshold

By G.J. Bell, T.G. Webster & V.J. Harber

Pages: 12 & 13

Reaction Time Analyses in the Sprint Starts

By B. Maraj, A. Brown & D. Collins, Ph.D.

Pages: 4 & 5

pulse

Winter 2007 Vol. 20 No. 1 SMCA Board of Directors President Dr. Gordon Bell, Ph.D. Past-President Koralee Samaroden, BPE, PFLC Vice-President Dwayne Laing, BPE, CAT (c) Treasurer Darren Turchansky, CA Secretary Cst. Jennifer Hanon ASSM Rep Position Currently Vacant SPC Rep Gabrielle Cave, BSc., P.T., MCPA AATA Rep Breda Lau, CAT (c) SSAA Rep Stephane Simard SNS Rep Jane Dawson-Edwards, R.D. Member at Large Ray Kardas SMCA Employees Executive Director Jennifer Johnson, BPE Accounts Manager Janice Peters, BCom Director of Programs Michael Pugh, BPE & Services Communications & Morgen Zoeller, BA PR Coordinator Pulse Magazine Published by:

Sport Medicine Council of Alberta 11759—Groat Road

Edmonton, Alberta, Canada T5M 3K6

Phone: (780) 415—0812 Fax: (780) 422-3093

Website: www.sportmedab.ca Email: [email protected]

Contents copyright 2007 by SMCA. Articles may not be reprinted without permission. The opinions are those of the respective authors and are not necessarily those of the SMCA. ISSN: 1181-9812 Publication agreement no. 40038086

THE SPORT MEDICINE COUNCIL OF ALBERTA

WOULD LIKE TO THANK THE:

AND ITS SPORT SCIENCE RESEARCHERS FOR

CONTRIBUTING THEIR ARTICLES TO THIS ISSUE OF

THE PULSE MAGAZINE.

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Latest News

from the SMCA

The Sport Medicine Council of Alberta Would Like to Thank our Partners for

their Ongoing Support: Sports Nutrition Course The SMCA has been working extremely hard to redevelop our Sports Nutrition Program. With a new presentation and participant workbook, our Sports Nutrition Level 1 Course will launch in the New Year. The course will tackle basic principles of sport nu-trition, including hydration, proper nutrition, competition nutrition and healthy weights. Participants will also receive a free coupon for a Nutrition Tour at Save-On-Foods.

NEW Resource Library Thanks to the generous support of Alberta Lotteries, through the Community Initiatives Grant Program, the SMCA has acquired fund-ing to purchase new resources for our Sport Medicine Resource Library! We have added the most up-to-date DVDs, videos, textbooks and multimedia to the library in the areas of sport nutrition, drugs in sport, athletic injury prevention and treat-ment, strength training and sport psychology. In addition to coaches and parents, most of the resources are geared towards students and athletes over the age of 12. However, there are some resources that target children in grades 1-6. Just as before, the SMCA will continue to ex-tend a two week complimentary borrowing policy to our members, with an unlimited number of books that may be borrowed per year. You can see all the new titles at www.sportmedab.ca/library.html.

AFA Conductor Forum The Athletic First Aid Conductor Forum has been postponed until February 2007. For more information, contact Mike at (780) 415-0812 or by email, [email protected].


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Reaction Time Analyses in the Sprint Starts Introduction It has been shown in multiple studies that acoustic stimuli intensity to that of a starter’s pistol can evoke a startle response, which also decreases reaction time (Carlsen et al. 2004, Valls-Sole et al. 1995). Also, research on the startle response has shown that as the auditory stimulus increases, the response magnitude and probability in-creases, and the response latency decreases (Blumenthal 1996). Objective The purpose of this experiment was to examine the effect of the intensity of an auditory “go” signal, in the form of a gunshot (audio file), on reaction time in a complex coordination task. Design Quasi-Experimental. Setting University of Alberta. Subjects Five male participants (age 18-42 yrs). The participants

had limited exposure to sprinting, but given that the reac-tion times for sprinters and non sprinters have shown negligible differences, the use of these less skilled partici-pants was warranted in this case. This study was approved by the Faculty of Physical Educa-tion and Recreation Research Ethics Board at the Univer-sity of Alberta.

Intervention/Main Outcome Measures Task The task utilized was a sprint start from starting blocks. Participants performed 2 blocks of 33 trials on separate days. Three go signal stimulus intensities were used: (low – 90 dB, medium – 100 dB, high – 110 dB) were used and their order was randomized. Thus there were 2 blocks of 10 trials for each of the intensities. Additionally, ten percent of the trials in each block were catch trials to ensure that participants were not anticipating the stimulus. Two verbal commands, “ready” and “set” (audio files ~80 dB), were delivered prior to the onset of the go signal. The foreperiod between set and go was held constant at 2 seconds since we were specifically interested in the effect of the intensity on the reaction time. Data Capture and Analysis Data were captured using a customized program to record the onset of the go signal and the change in force measured with a force sensitive resistor attached to the back of the starting blocks. The stimulus intensities were verified with a digital sound level meter.

By B. Maraj, A. Brown and D. Collins, Ph.D. University of Alberta Edmonton, Alberta, Canada


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.ca The group data were analyzed using a one-way

repeated measures analysis of variance (ANOVA). Main Results The results indicated a significant main effect (F(2,8) = 18.62, p< .001). Post hoc analysis (Tukey’s HSD) revealed that the high intensity trials produced significantly shorter reaction times (133+8 ms; mean+SD) compared to the medium (143+4 ms) and high (150+8 ms) intensities, which were not significantly different from each other. Conclusions We suggest from these results that a startle type effect may influence reaction time of a complex coordination task and have implications for standardising sprint start procedures. Source of funding Sport Science Association of Alberta (SSAA) through the ASRPWF. For more information, Contact: Dr. Brian Maraj, Faculty of Physical Education and Recrea-tion, W1-16F Van Vliet Center, University of Alberta, Edmonton, Alberta, Canada, T6G 2H9. Commentary The start is an important and critical element in many sprint races. In athletics (track and field), the margin of difference in the reaction time to the starting gun may be the difference between gold and finishing out of the med-als. Given this, we sought to find factors that could play a role in facilitating reaction times for athletes in this com-petitive context. That the increased intensity of the stimulus had a significant effect on reaction times, further research is warranted to examine the extent to which any advantage is being gained and if so, explore means by which to level the playing field for all competitors.

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January 20 & 21, 2007 March 10 & 11, 2007 Calgary Edmonton


FOR MORE INFORMATION, CHECK OUT WWW.SPORTMEDAB.CA, OR CALL (780) 415‐0812.

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Introduction Most studies have examined movement skills or strategies in baseball or fast-pitch softball. Few studies have looked at slo-pitch softball specifically. Some researchers believe that in slo-pitch, a ball is thrown in a parabola arc due to the influence of gravitational force only (Simonian, Funda-mental of Sports Biomechanics, 1981). The effect of air resistance on the ball in flight is considered to be minimal. However, Dowel et al. (J. of Hum. Mov. Studies, 11: 209-221, 1985) pointed out that when the ball in flight is af-fected by air resistance, it actually travels in a skewed curve path. When a non-smooth and asymmetrical ball is thrown in the air, it experiences lift, drag and cross-sectional forces (Alaways and Hubbard, J. of Sports Sci-ences, 19: 349-358, 2001). Many slo-pitch coaches and players believe that generating the spin on the ball can affect its trajectory even if the ball is thrown with such slow speed. Nevertheless, the effect of air resistance on the ball trajectory in underhanded pitching remains unan-swered, especially the correlation relationship between horizontal distance and different types of ball spin. Objective The purpose of this study was to examine the influence of spin in slo-pitch pitching. This experiment’s aim was to determine whether or not the angular velocity along with any potential influences from air resistance could result in a change in the horizontal displacement of the ball. It was hypothesized that when a ball was thrown under-handed in an arc with top spin, the ball would fall shorter due to the Magnus effect and would have a greater range with back spin. Design Quasi-experimental design. Setting University of Alberta, Edmonton. Subjects The subjects (n = 11 males and 3 females) were recruited from local division A or B slo-pitch leagues. This study was approved by a University Research Ethics Board. Intervention/Main Outcome Measures Each subject stood on a pitching plate that was 15.2 m (50 ft) away from an indoor home plate with an extension strike zone mat. Subjects were asked to throw five top

spin pitches and five back spin pitches. Each pitch was considered successful if the ball was thrown with a mod-erate speed and landed on the extension strike zone mat with an arc of between 1.83 m (6 ft) and 3.66 m (12 ft). The speed, height, and location of the ball were subjec-tively monitored by an experienced slo-pitch player/experimenter in the same manner as in a real game situa-tion with an umpire. If a pitch was thrown unsuccessfully, the subject was asked to repeat that particular pitch. The subject had at least 30 seconds rest between each pitch and 1 min rest between each type of pitch. Each subject’s involvement in the study was limited to one data collec-tion session, approximately 1.5 hours in length. Twelve “Approved by Softball Canada” Dudley Spalding synthetic Thunder Heat 0.30 m (12”) optic with C.O.R. 47 balls were used. Balls were marked, with a black marker, to divide them into four equal quadrants to monitor ball spin. Video of the pitches was collected using standard three- dimensional videography using 5 digital video cameras operating at 60 Hz with shutter speed set between 1/250s to 1/1000s. The first, second and third cameras were positioned at approximately 60° apart to each other to capture the release of the ball in sagittal and frontal views. The fourth camera was positioned perpendicular to the pitching motion to allow a close-up sagittal view of ball spin. The fifth camera was positioned perpendicular to the sagittal view of the home plate and strike zone exten-sion mat to capture the landing location of the ball.


By P. Gervais and T. Wu University of Alberta Edmonton, Alberta, Canada

An Examination of Softball Slo-pitch: Effects of Spin on Ball Trajectory

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Main Results A paired sample t-test was conducted between the top spin and the back spin variables. The horizontal and verti-cal velocities in the back spin were significantly higher than in the top spin. The angular velocity of the back spin was found to be 65.0 ± 2.7 rad/s, which is also significantly higher than the top spin of 42.3 ± 3.4 rad/s. The throwing distance of the back spin (14.8 ± 0.4 m) was significant further than the top spin (14.5 ± 0.4 m). No significant difference was found in the stride length used in these two pitching techniques. Conclusions The results from the experiment suggest that the air resis-tance had an influence on the ball’s trajectory even if the ball was thrown in the range of 6.0 to 10.0 m/s in the horizontal and vertical velocities. The back spin pitches projected 0.30m further than the top spin pitches in the horizontal distance. In order to determine the exact mag-nitude of air resistance to the ball,

future studies will require the use of a wind tunnel and a ball flight simulation.

Source of funding Sport Science Association of Alberta (SSAA) through the ASRPWF.

For more information, Contact: Dr. Pierre Gervais, Faculty of Physical Education and Rec-reation, W2-60 Van Vliet Center, University of Alberta, Edmonton, AB, T6G 2H9.

Commentary When a ball is thrown with spin, it creates a high velocity and low pressure area on one side of the ball and a low velocity and high pressure area on the other side of the ball. These pressure differences result in a lift force on the ball directed from the high to the low pressure region. This is known as the Magnus effect. Hence, when a ball is thrown with a top spin, the ball will travel shorter dis-tance than a ball that is thrown with a back spin. In this experiment, when a ball was thrown with a back spin, it had higher horizontal and vertical velocities and greater angular velocity. Therefore the ball had a higher skewed arc trajectory and a longer horizontal distance. The result of longer horizontal distance may simply be due to throw-ing the ball with higher horizontal and vertical velocities. Whether or not spin alone is sufficient to influence the trajectory, will require the use of wind tunnel testing to determine the coefficient of lift and drag forces. This information can then be used in a flight simulation to pre-dict its precise landing location.


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Introduction Leptin, a hormone made by adipocytes and the protein product of the ob gene, is an important circulating signal for the regulation of body weight (Zhang et al., 1994). It interacts with specific receptors in the hypothalamus af-fecting appetite and satiety centers of the brain (Rohner-jeanrenaud & Jeanrenaud, 1996). Since its discovery in 1994, the physiological roles of leptin have broadened. Our ability to translate current leptin data into clinical utility is limited due to; 1) the lack of appropriate values for leptin in reference populations, and 2) differences in assay methodology. Objective This study examined normative reference ranges for total plasma leptin in elite athletes between 18-30 years of age who were involved in sport science support. The ath-lete’s height, weight, (calculated BMI), triglyceride, total cholesterol, HDL-cholesterol, LDL-cholesterol, glucose and insulin were measured to ensure that the athletes were within the healthy status range. Design Cross-sectional-descriptive study.

Setting Human Performance Laboratory in University of Calgary, Calgary Laboratory Services, and Alberta Children’s Hos-pital, Calgary AB. Subjects Seventy-six elite male and female athletes. Intervention/Main Outcome Measures All subjects were sampled following at least a 12 hour fast. The volunteer’s height and weight were recorded at the time of blood collection and used to calculate their body mass index (BMI). Following procurement of the clinical specimens required by the sport centre, a second vacutainer (3ml) was obtained. Triglyceride, total choles-terol, HDL-cholesterol, LDL-cholesterol (calculated), glucose and insulin were analyzed according to estab-lished Calgary Laboratory Services methodology. Total plasma leptin was analyzed by enzyme linked immunosor-bent assay (ELISA; Linco Research, Inc.). However, we were unable to determine free and bound values due to the current kit limitations and because the lab was being renovated during the study.

By PK. Doyle-Baker, A. Venner and ME. Lyon University of Calgary Calgary, Alberta, Canada


Investigation of Total, Free and Bound Leptin in Olympic Development Athletes

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Two athletes were excluded from results because they were over 30 years of age (N=76). The physical character-istics of the remaining athletes are included in Table 1. Table 1. Participant characteristics of all athletes (n=74).

*n=48, undetectable in 36 athletes All athletes were considered healthy based on their lipid, insulin and glucose profile. Plasma leptin concentrations ranged from <0.5 – 19.15 ng/ml. The sample was sepa-rated by sex and divided into sprint and endurance ath-letes. Sprint sports included hockey, luge, skeleton and wrestling. Endurance sports included biathlon, speed skat-ing, track and field and cross-country skiing. Leptin con-centrations were undetectable (<0.5 ng/ml) in all cross-country skiers (n=11), all track and fielders (n=2), all male speed skaters (n=5), all male biathletes (n=5) and one female speed skater. Sprint athletes (n=34) had a plasma leptin concentration of 6.58±4.71. There was a significant difference between female (n=27) and male (n=7) sprint athletes (p=0.004). There was no significant difference between sprint athlete leptin concentration and BMI (p=0.67). The endurance group had many undetectable vaues, therefore the nonparametric Mann-Whitney Test was used to compare endurance versus sprint athletes. There was a significant difference between leptin concen-tration in the two groups (p<0.0001). There was a signifi-cant difference in BMI between sprint and endurance ath-letes (p=0.0006). Sprint athletes had a BMI of 24.53±2.25 and endurance athletes had a significantly lower BMI of 22.87±1.73.

Summary and Conclusions This study demonstrates that plasma leptin concentrations in elite athletes range from <0.5 to 19.15 ng/ml.

Variable Mean ± S.D. Age (yrs) 23.46±3.36

Height (cm) 174.31±7.57

Weight (kg) 72.09±9.23

BMI (kg•m2) 23.68±2.15

Fasting Glucose (mmol/L)

4.81±0.29

Total Cholesterol (mmol/L)

4.34±0.070

Triglyceride (mmol/L) 0.86±0.86

HDL-Cholesterol (mmol/L)

1.61±0.04

LDL-Cholesterol (mmol/L)

2.34±0.07

Total-C:HDL Ratio (mmol/L)

2.78±0.07

Insulin (pmol/L) 38.24±1.82

Leptin (ng/ml)* 5.91±4.44

More specifically, endurance athletes have a significantly lower leptin concentration than sprint athletes. Additionally, endurance athletes have a significantly lower BMI than sprint athletes. Further research is needed with a larger sample size to confirm these results. Additionally, trying to increase the sensitivity of the ELISA kit will aid in increasing our understanding of leptin in elite athletes.


For more information, Contact: Dr. PK Doyle-Baker or Ms. Ali Venner, 2500 University Drive NW, HPL, Faculty of Kinesiology, University of Cal-gary, Calgary, AB, T2N 1N4.

Commentary Leptin is a metabolic variable that does not respond to energy intake or exercise energy expenditure, but it does to the balance between the two. This initial study provides direct values for plasma leptin concentration in a variety of different athletes. Additionally, it provides healthy ref-erence ranges for their lipid, glucose and insulin profile. The significantly lower leptin concentrations seen in en-durance athletes relate to the lower BMI found in these athletes. The increase in aerobic capacity for endurance athletes enables them to have more efficient use of lipid metabolism through β-oxidation. This allows for a de-crease in fat mass, and thereby, a decrease in leptin being produced and secreted from adipocytes. Furthermore, the significant difference in leptin concentrations across male and female athletes is in line with much of the published literature. As females tend to have a higher fat mass and BMI, they will also have higher amounts of leptin being released from their adipocytes. The analysis of elite ath-lete blood variables increases our physiological under-standing of how training may affect leptin, BMI and health status. In order to more accurately compare and analyze leptin concentrations in this population, it is important to try and increase precision of current ELISA techniques. Presently it is unknown what role leptin plays in sport performance. However, as our understanding of leptin increases, it will be a possible to identify if it plays a critical role in training prescriptions in some sports.


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Physiological Characteristics of Female Varsity Rugby Union Players Introduction Rugby Union is now played competitively in 95 countries throughout the World. Currently, women’s teams com-pete at the national, club, high school and mini levels all across the country. However, few scientific investigations have attempted to characterize the physiological attrib-utes of rugby players and those that have, have recruited only male players2-4. As well, there is clearly a lack of re-search documenting the characteristics of elite rugby play-ers compared to those in the club and developmental levels2. Furthermore, there are presently no fitness stan-dards for coaches and trainers to compare their players to those who compete at the elite or sub elite levels. Therefore, it was the aim of this research to evaluate the anthropometric and physiological characteristics of female players from the Edmonton and surrounding area to document both the unique positional characteristics of female rugby players but also to evaluate the differences between elite (National and Provincial) compared to non elite (club and high school) players. Objective The purpose of this study is to evaluate the anthropomet-ric and physiological characteristics of female rugby play-ers. A secondary aim will be to assess the position specific and standard specific differences between these players. Design Single group, quasi-experimental. Setting University of Alberta, Edmonton. Subjects Twenty-nine female rugby athletes (1 did not complete testing due to injury) completed the battery of tests. (Forwards (n=16) and Backs (n=12)). This study was ap-proved by a University Research Ethics Board.

Intervention/Main Outcome Measures The anthropometric characteristics of all subjects are listed in Table 1 and the physiological assessment out-comes are presented in Table 2. All testing was performed in the Sport and Health Assessment Centre and other associated facilities at the University of Alberta.

Main Results Table 1. Anthropometric measurements. Values are means and SD.

Table 2. Physiological measurements. Values are means and SD.

= Significant difference between back and forward results (p<0.05)

Variables Squad Backs Forwards Age (yrs) 22.6 ± 3.0 23.1 ± 3.1 22.3 ± 3.0 Experience (yrs) 6.4 ± 2.4 6.8 ± 1.7* 6.1 ± 2.9 Height (cm) 168 ± 6 164 ± 5 171 ± 6* Weight (kg) 71.1 ± 12.1 65.3 ± 6.1 75.5 ± 13.8* Skinfold (mm) 181.4 ± 40.2 162.1 ± 25.3 195.9 ± 43.8*

Variables Squad Backs Forwards Sit & Reach (cm) 36.4 + 7.2 35.1 + 6.4 37.4 + 7.8 1RM Bench (kg) 49.5 + 10.9 54.9 + 13.6* 45.2 + 5.6 1RM Squat (kg) 87.9 + 21.1 97.1 + 16.4 80.7 + 22.1 VO2max (ml/kg/

min) 43.7 + 3.7 44.0 + 3.0 43.4 + 4.2

VO2max (l/min) 3.1 + 0.4 2.9 + 0.4 3.2 + 0.3* 35m Sprint (sec) 5.66 + 0.32 5.48 + 0.19* 5.80 + 0.35 Illinois Agility (sec) 21.03 + 1.83 19.86 +

0.72* 22.04 + 1.37


By A.B. Game and N.D. Eves University of Alberta Edmonton, Alberta, Canada

Conclusions Forwards were taller, heavier and had a greater SOS and absolute VO2max than backs. In contrast the backs were faster, more agile and had a higher bench press than the forwards. These results correspond to positional requirements and are consistent with previous work with males [1,2] except for the sup- erior upper body strength of the backs. The finding that the backs were stronger than the forwards was unexpected as the requirements of forward play are mainly associated with ball winning and retention which requires a high level of strength. These differences may be explained by the significantly longer playing experience and training history of the backs in this sample. Further evaluation is now required to substantiate these findings and establish differences between specific positions as well as between players at different representative levels. Source of funding Sport Science Association of Alberta (SSAA) through the ASRPWF. For more information, Contact: Alex B. Game, MSc, PFLC, Faculty of Physical Education and Recreation, E-473 Van Vliet Center, University of Alberta, Edmonton, AB, T6G 2H9.

Commentary Women’s rugby is one of the fastest growing sports in Alberta and now there are teams for females at junior,

high school, varsity, club and representative level. Alberta is one of the countries strongest provinces for female rugby and provides approximately 12-15 players to the full Canadian Squad and U23 developmental team. In addition to this the University of Alberta team is one of the strongest varsity teams in the country and the cities of Edmonton and Calgary both boast a number of very com-petitive female club sides. As well, Edmonton will be hosting the Women’s Rugby World Cup in the fall which will further the interest in women’s rugby. The results from this study give coaches fitness standards for their players to strive to achieve and will ultimately raise the level of women’s rugby in the province.


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Introduction The existence and measurement of anaerobic threshold has been a controversial topic but remains a pivotal meas-ure within exercise and sport science (Hollmann, 2001; Svedahl & Macintosh, 2003). Blood lactate measurements and ventilatory parameters have been the most widely used methods of anaerobic threshold determination and have been examined for reliability and validity (Wasserman et al, 1972; Bhambhani and Singh, 1980; Wasserman, 1984; Prud’homme et al, 1984). A method of threshold identification using blood glucose measurement has been supported as a possible alternative or addition to these established measures (Northius et al, 1995; Simoes et al, 1999; Simoes et al, 2003; Ribeiro et al, 2004). This glucose response to graded exercise follows the identifica-tion of a low point or nadir in blood concentration during exercise and has been shown to evaluate aerobic capacity as well as being related to the lactate and ventilatory thresholds (Simoes et al, 1999). Objective The purpose of this study is to investigate the response of serum glucose levels and the associated hormones gluca-gon, insulin and cortisol to incremental exercise. It was hypothesized that there is a nadir of serum glucose

which occurs in a predictable fashion to anaerobic thresh-old. It was further hypothesized that the occurrence of glucose threshold would be mirrored by the increased concentration of glucagon and cortisol, and decreased concentration of insulin to maintain euglycemia amidst the metabolic demands leading up to and beyond anaerobic threshold. Design Quasi-experimental design. Setting University of Alberta, Edmonton. Subjects Twenty-two healthy active males residing in the city of Edmonton volunteered to participate in this investigation. A healthy, active individual was defined as a person who participated in regular aerobic physical activity a minimum of 3 times a week and was free of conditions that may have impeded their metabolic function or their effort and performance during the graded exercise test. This study was approved by a University Research Ethics Board. Intervention/Main Outcome Measures The exercise testing involved three visits to the exercise physiology lab. One session for maximal oxygen con-sumption (VO2 peak) testing, one for anaerobic threshold (AT) testing, and a third for a fasted blood sample. The peak VO2 test was conducted first to also provide partici-pants with experience to the testing environment. Be-tween 2 and 5 days after the peak VO2 test the partici-pants returned to the lab in the rested state for the AT test. This test included blood samples taken at rest be-fore exercise and in the last minute of each power output.


The Nadir in Serum Glucose as a Predictor of Anaerobic Threshold

By G.J. Bell, T.G. Webster and V.J. Harber University of Alberta Edmonton, Alberta, Canada

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Between 2 and 5 days after the AT exercise test and the morning after an overnight fast, the participants returned on a different day to provide a fasting blood sample. The exercise testing was conducted on a cycle ergometer beginning at 74w and 75 rpm and increasing by 37w every 2 minutes in the VO2 peak test and every 3 minutes in the anaerobic threshold test. Blood was analyzed for glucose, glucagon, insulin, cortisol and lactate.

Main Results An identifiable nadir in serum glucose was observed in 20 of 22 participants. There was no significant difference between the workloads of lactate threshold and the nadir in serum glucose. There was a significant difference (p<0.05) and a significant correlation with the nadir in serum glucose and ventilatory threshold, with the ventila-tory measure being approximately one workload greater than the glucose measure. In hormone analysis, insulin was significantly lower and glucagon significantly higher after the nadir in serum glucose.

Conclusions These observations support the nadir in serum glucose as a predictor of anaerobic threshold and also provide possi-ble evidence for the hormonal mechanism of this associa-tion. It was concluded that during a graded exercise test a nadir in serum glucose does occur in predictable fashion to ventilatory threshold and thus, the exercise intensity of optimal serum glucose clearance may be identifiable.


For more information, Contact: Dr. Gordon Bell, Faculty of Physical Education and Rec-reation, E424 Van Vliet Center, University of Alberta, Edmonton, AB, T6G 2H9.

Commentary Anaerobic threshold has been widely used as an indicator of aerobic fitness and as well as a marker for exercise training intensities. The most often used methods of threshold determination have been lactate and ventilatory measures with the use of glucose only recently being pub-lished. This study was performed in continuation of the previous research to provide further evidence of the rela-tionship between glucose metabolism and anaerobic threshold and to provide new research on the hormones glucagon, cortisol and insulin related to the glucose threshold, as it had not been previously examined. The present findings agree with previous research in finding a relationship between the nadir in serum glucose and the anaerobic threshold. Further, the current findings suggest a possible hormonal mechanism for this association as insulin was significantly lower and glucagon significantly higher after the nadir in serum glucose. The significance these findings includes the further information for the research community, as well as support for the use of the glucose nadir as a possible alternative for anaerobic threshold determination in athletic populations.

NEW Resource Library! Thanks to the generous support of Alberta Lotteries, through the Community Initiatives Grant Program, the SMCA has acquired funding to purchase new resources for our Sport Medicine Resource Library! We have added the most up‐to‐date DVDs, videos, text‐books and multime‐dia to the library in the areas of sport nutrition, drugs in sport, athletic injury prevention and treatment, strength and training and sport psychology. Just as before, the SMCA will continue to extend a two week complimen‐tary borrowing policy to our members. Check out www.sportmedab.ca/library.html to see a listing of all resources, or call (780) 415‐0812 for more information.


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Introduction The importance of saving cycling energy is still relevant and remains as an active research area for both sport and daily activities. The fam- ous yearly competition – Tour de France – is essentially a competition of human power and energy-saving strategies. Bike Power Saver (BPS) is a new product which changes the angle of pedaling forces and reduces applied power dead range (Product Ad). However, no research is found to examine how the new product aff- ects pedaling as well as its influence on fatigue of cycling. The proposed study attempts to address this problem. Objective The goals of this proposed research were: 1. To study a new bike power saver product available

on the market (A scientific evaluation of a new industry product is essential for protection of cus-tomer’s interests).

2. To reveal the influences of the new device on con-trol patterns.

3. To quantify the effectiveness of the product using biomechanics.

Setting The measurements were conducted in the Biomechanics Lab at the University of Lethbridge. Subjects This study involved 10 kinesiology students aging from 20 – 27 years old (5 females and 5 males) from the University of Lethbridge. Intervention/Main Outcome Measures From motion capture, we can obtain anatomical positions that allow the modeling of the skeletal structure, which enables the calculation of dynamic joints’ angles. In order to evaluate the effectiveness of BPS, we used parameters of pedal paths and joints’ ranges of motion with and without BPS. To contrast the neural muscular differences, we collected, through EMG, the intensity of muscle activation, the average muscle activity and the muscle power generation.

For evaluating muscle fatigue process, the decline rate of EMG’s mean power frequency from long-time tests was applied. Main Results The BPS can be summarized: 1) to entice instability in an-kle control, 2) to change improperly the pedal-crank length during cycling, 3) to increase the activities and the bio-energy consumed by dominant muscles (i.e. quadri-ceps and tibialis anterior) and 4) to induce an accelerated fatigue process for these muscles. These results lead to the conclusion that the Bike Power Saver Device decreases the efficiency of bicycling. Source of Funding Sport Science Association of Alberta (SSAA) through the ASRPWF. For more information, Contact: Dr. Gongbing Shan, Dept of Kinesiology, UofL 4401 University Dr, Lethbridge, AB, T1K 3M4 e-mail: [email protected]

By G. Shan, Ph.D. University of Lethbridge Lethbridge, Alberta, Canada


Evaluation of the Bike Power Saver through 3D Kinematics and EMG Analysis

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Lister Conference Centre at the University of Alberta and Conference Services hosts events and conferences all year long…

Did you know? In the heart of the city, the University of Alberta Conference Services Department is bubbling with activity all year long. Conference Services at the University of Alberta has been creating successful events for over 20 years with a team of expert conference coordinators to assist you every step of the way! • Over 18,000 sq. ft. Conference Centre (8 meeting rooms) are open all-year round. We host all types of events; from

board meetings, to weddings to national conferences. Ask us about our booking lecture theatres, smart classrooms and our unique venues.

• The Hotel at Lister Centre features 20 guestrooms –available year-round offering a great nightly rate which includes complimentary parking, continental breakfast at Tim Horton’s ( on-site) , local calls and internet access.

• May through to August we can accommodate over 1500 guests in our dorm-style rooms in (3) three residences; Lister Hall, Schaffer Hall and our Francophone accommodation Residence Saint-Jean (located at the Faculty Saint Jean cam-pus). Choose from Traditional Dormitory (shared bath) or Private Dormitory style rooms (twin rooms or single rooms).

• Team of Professional Conference Coordinators are on staff to handle your event form beginning to end. • Classic Fare Catering offers a full menu quality catering with exceptional service for any event - from a board meeting to

a special gala. • Planning meetings; large or small, conferences local or international, special events or graduations,

a wedding or Christmas party, our TEAM can create unforgettable memories.

For more information on planning your next meeting, event or conference, contact us today: Main line: (780) 492.6057

Email: [email protected] For more information on booking rooms for your group or just need a guestroom for a night contact:

Email: [email protected] Check us out: www.ualberta.ca/conferenceservices

Documents

Winter 2007