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The purpose of this study was to examine the effects of a 4-week reduction in training volume and intensity on performance of distance runners. Ten well-conditioned males underwent 4-weeks of base training (BT) at their accustomed training distance (71.8 ± 3.6 km/wk) and pace (76% of total distance above 70% V02 max intensity), before reducing training (RT) for an additional 4 weeks. Training volume was decreased by -.66% to 24.8 km/wk and frequency by 50% to 3 runs per week. Training intensity was reduced such that all running was at less than 70% V02 max (68.2 ± 1.6%). At the end of BT (week 0), and weeks 2 and 4 of RT, resting heart rate, calculated plasma volume, testosterone and cortisol levels, and submaximal treadmill efficiency were assessed. At weeks 0 and 4, V02 max and 5 kilometer race performance was determined. The ratio of testosterone to cortisol was increased significantly with RT (0.054 ± 0.008 at week 0 to 0.082 ± 0.020 at week 4), although the individual testosterone and cortisol concentrations were not significantly altered. Maximum oxygen consumption, and time to exhaustion during the max tests were not altered with RT. Body weight tended to increase (p=0.09) due to a significant increase in percent body fat (p<0.05). Submaximal treadmill runs at 65%, 85%, and 95% V02 max revealed no alterations in absolute V02 while relative V02 decreased significantly. This decrease in relative V02 was due partially to the weight increases and partially to a significant increase in respiratory exchange ratio (RER). Resting and submaximal treadmill heart rate (HR) were unchanged with FIT, while maximal treadmill HR and race HR were increased significantly. Calculated plasma volume was unaltered. Leg and overall ratings of perceived exertion were decreased during RT with the overall rating reaching significance (p<0.05). Blood lactic acid concentration was found to be significantly higher at the 95% V02 max workload following RT (8.39 ± 0.46 vs 9.89 ± 0.46 mmol/L at week 0 and 4, respectively). Five kilometer race time increased significantly from 16.6 ± 0.3 at week 0 to 16.8 ± 0.3 minutes at week 4 (12.1 seconds). It is concluded that a 4-week reduction in training volume and intensity in these runners resulted in a significant decrease in race performance despite the maintenance of aerobic capacity. / School of Physical Education

There has been an interest in the kinetics of the V02 response during exercise at various intensities. However, most studies focus on the response of submaximal intensities whereas few studies have examined V02 kinetics at severe intensities. The purpose of this study was to evaluate the effect of exercise intensity on V02 kinetics over a range of severe intensities.

There were two primary goals in this investigation. The first goal was to determine if inter-individual variability in time to exhaustion at the velocity associated with V02max (Tlim at Vmax) was explained by anaerobic capacity (AC), Vmax, anaerobic threshold (AT), and/or a combination variable in the form [AC • (Vmax - vAT)^-1]. The second goal was to determine if AC could be predicted from Tlim at Vmax, AT, and/or a combination variable in the form [Tlim • (Vmax - vAT)].

Eighteen subjects each performed fifty-five trials which consisted of assuming an initial stance and then in response to a visual stimulus running to either the left or right. For each trial both the foot width spacing and orientation of the feet were varied. Direct and indirect measurements were taken of selected temporal and kinematic parameters. The conclusions were that no interactions or differences exist among foot width spacing, foot orientation, and direction of movement; the jab step start is the preferred initial movement; the preferred foot width spacing is 46.6 centimeters; the preferred angular orientation of both feet is approximately 1.36 radians.

Fast medio-lateral movements, frequent in a number of sports activities, are associated with lower extremity injuries. These injuries may occur as a result of excessive musculoskeletal stresses on the joints and their associate structures. The purpose of this study was to investigate the effect of running speed and turning movement on the three-dimensional moments at the ankle, knee, and hip joints. Data were collected using video cameras and force plate. Eight male recreational basketball players were tested during slow (1.5 m/s), moderate (3.0 m/s), and fast running (4.5 m/s) and when cutting to the right or left (+60, +30, 0, -30, and -60��). The inverse dynamics approach was used to integrate the body segment parameter, kinematic and force plate data, and to solve the resultant joint moments. At the ankle joint, inversion/eversion, dorsi/plantar flexion, and internal/external rotation moments of the ankle joint increased with running speed (p<.05). At the knee joint, flexion/extension and abduction/adduction moments increased with running speed except flexion moment that decreased with running speed (p<.05). At the hip joint, internal/external rotation, flexion/extension, and abduction/adduction moments increased with running speed (p<.05). In medial cutting movements, greater abduction moments of the ankle, adduction moments of the knee and external rotation and adduction of the hip were found (p<.05). In lateral cutting movements, greater inversion and adduction moments of the ankle, abduction moments of the knee and hip were found (p<.05). These findings reinforce the intuitive notion that fast medio-lateral turning movements produce substantially greater musculoskeletal loading on the joint structures than does straight running and consequently have greater potential for inducing lower extremity injuries such as ankle sprain or anterior cruciate ligament injury. / Graduation date: 1999

The purpose of this study was to examine the vertical component of the American College of Sports Medicine (A.C.S.M.) Guidelines equation to predict the oxygen cost of grade running. The A.C.S.M. Guidelines equation is: VO$ sb2$(ml/kg.min) = 3.5 + 0.2 speed(m/min) + 0.9 (speed(m/min) * grade(frac)). Twenty-three female runners (20 to 33 years) participated in (1) a VO$ sb2$max test, (2) five 6 min running economy (RE) tests at 133 m/min, (3) five 6 min RE tests at 160 m/min, and (4) three 6 min RE tests at 186 m/min. The RE tests at 133 and 160 m/min were performed at the following grades: 0, 2.5, 5.0, 7.5, and 10.0%. The RE tests at 186 m/min were performed at 0, 2.5, and 5.0% grade. The RE tests were administered in random order. There was a linear relationship between VO$ sb2$ and horizontal running velocity with a slope of 0.20 ml/kg.m (r = 0.996; p $<$.01). There was a linear relationship between VO$ sb2$ and percent grade when running on a treadmill. The correlations for the regression equations at speeds of 133, 160, and 186 m/min were 0.90 (p $<$.01), 0.86 (p $<$.01), and 0.73 (p $<$.01), respectively. Inclusion of a grade component in the regression analysis equation increased the accuracy for predicting the VO$ sb2$ of grade running. VO$ sb2$ consumption for grade running can be predicted using the following equation: VO$ sb2$ (ml/kg.min) = 3.5 + 0.198(speed in m/min + 0.932 grade(%)) + 0.006(speed(m/min) * grade(%)). The new equation explained 99.5% of the variance (R$ sp2$) compared to the 78.0% of the variance (R$ sp2$) that was explained by the A.C.S.M. Guidelines equation.

Six runners (V02 max=68.2 ± 3.4 ml/kg/min) were studied on three separate occasions during a 30 min treadmill run at 70% V02 max. On each occasion, the subjects ingested either 75g of glucose (trial G), fructose (trial F) or a sweetened placebo (trial C). No differences were observed between any of the trials for oxygen uptake, heart rate or perceived exertion. Serum glucose levels were elevated as a result of the glucose feeding (P<0.05) reaching peak levels at 30 min post-feeding. With the onset of exercise, glucose levels dropped to a low of 5.89 ± 0.99 mmol/l at 15 min of exercise in trial G. Serum glucose concentrations in trials F and C averaged 6.21 ± 0.31 mmol/l and 5.95 ± 0.23 mmol/l over all the time points, respectively, and were not different (p>0.05). Muscle glycogen utilization in the first 15 min of exercise was similar in trial C (18.8 ± 1.9 mmol/kg), trial F (16.3 ± 4.1 mmol/kg) and trial G (18.8 ± 9.1 mmol/kg), and total glycogen use was also similar in trial C (20.7 ± 5.3 mmol/kg), trial F (35.4 ±6.3 mmol/kg) and trial G (25.6 ± mmol/kg). These data suggest that pre-exercise feedings of fructose or glucose do not affect the rate of muscle glycogen utilization during 30 min of treadmill running in well-trained runners.

Human locomotor economy and efficiency are highly variable. This study investigated the role that stature plays in this variation, by evaluating metabolic and respiratory responses to walking and running at speeds set relative to one's stature. Four groups of subjects: male, high V0₂ max (n = 11); male, average V0₂ max (n = 10); female, high V0₂ max (n = 10); and female, average V0₂ max (n = 11) were habituated to treadmill locomotion prior to the measurement of maximal oxygen consumption (V0₂ max). The V0₂ max test entailed 1 km.h⁻¹ increases per min from 3 to 6 km.h⁻¹ walking, and 7 - 17 km.h⁻¹ running then 1% grade increments per min until exhaustion. On each of four other occasions, the subject walked or ran at 6 of a variety of relative speeds - walking at 0.5, 0.7, 0.9, 1.1, 1.3; running at 1.5, 1.7, 1.9 and for selected subjects 2.1, 2.3 and 2.5 statures.s⁻¹ ,and grades - 0%, +3%, -3%. Steady-state respiratory and metabolic responses, and treadmill speed were monitored by an on-line computer system developed for this study. Cadence and RPE were also monitored. All subjects demonstrated an exponential relationship between V0₂ and walking relative speed (st.s⁻¹) (RS) . V0₂ (ml.kg⁻¹.min⁻¹ ) = 4.747 * e(1.371*RS) During running this relationship was essentially linear . The variability of economy at relative speed (9.08%) and absolute speed (9. 01%) did not differ. Male and female subjects did not differ in response to absolute speed but females were more economical at relative speeds (p<0.05). Those with high and average aerobic capacity did not differ in locomotor economy at relative speed. Higher freely-chosen stride length was associated with a higher V0₂ response as velocity increased. The V0₂ of uphill walking was 1.4 times greater than that for downhill walking (running: 1.28 times) . Stride length decreased with increasing speed in uphill locomotion but the reverse was the case for downhill. The economy and efficiency of walking was greater than that of running. Walking economy was maximal between 0.7 and 0.9 st. s⁻¹. Running economy remained essentially unaffected by increased velocity. The setting of locomotor velocity relative to stature does not minimize inter-subject variability in metabolic and respiratory response .

Background: Despite the introduction of running footwear in the 1970’s, running injury rates continue to be unacceptably high. The subsequent revival of barefoot running and the introduction of minimalist footwear occurred, in an attempt to reduce injury rates and increase performance. There is much contention in the literature around the effectiveness of these footwear conditions. Furthermore individual responses have recently been proposed to provide more accurate and reflective conclusions than the use of mean data. Objectives: Twofold: a) to compare the biomechanical, physiological and perceptual responses between the shod, minimalist and barefoot footwear conditions and b) to assess and compare individual responses under these footwear conditions. Methods: 26 well-trained, male, habitually shod endurance runners, aged between 18 - 30 years completed three experimental sessions on an indoor runway and motorized treadmill. Each session was completed in either the shod, minimalist or barefoot condition, running at 15km.h-1. Variables assessed included stride rate, stride length, impact peak, vertical impact and average loading rate and strike time (biomechanical); heart rate, oxygen consumption and electromyography (physiological); and rating of perceived exertion and body discomfort (perceptual). Results: Biomechanics – Stride rate and stride length showed a significant (p<0.001) increase and decrease respectively when running in the minimalist or barefoot conditions versus shod. Running barefoot versus the minimalist and shod conditions resulted in a significantly (p<0.001) greater vertical impact loading rate. Strike time was significantly (p=0.008) reduced running in the minimalist and barefoot conditions versus shod. Physiology – Running barefoot versus shod resulted in a significantly (p=0.02) reduced heart rate and Tibialis Anterior activity (p=0.005). There was a large variability in individual responses for many variables, with responders and non-responders seen. Conclusion: The study suggests that there are significant differences between all three forms of running for some variables. It was further noted that there is support for the proposal that individual responses are highly variable and should be analysed accordingly