Previous reports have demonstrated that running economy (RE), a measure of efficiency of locomotion, is superior in adults than in children; however, it is unclear how these differences come to be. Purpose: To identify the effect of maturity status, physical activity and various other anatomical and physiological factors on RE development in boys aged 8 to 16 years. Methods: Data were collected as part of the Saskatchewan Growth and Development Study (SGDS; 1964-1973). Using a pure longitudinal study design, anthropometric, maturity, physiological characteristics (treadmill run) and physical activity were assessed annually for nine consecutive years. Two-hundred and two eight year-old males were measured in 1965; by 1973, complete longitudinal data were available for 63 participants. During the treadmill run, a measure of submaximal oxygen consumption (VO2) was recorded, an index of RE. Four approaches of normalizing VO2 to body size were investigated. Maturity status was determined based upon chronological age at peak height velocity (PHV). Physical activity was assessed by two teacher ratings and two questionnaires. Results: Normalizing VO2 to body surface area was found to be the most appropriate body size adjustment. Submaximal VO2 (ml/m^2/min) at 9.6 km/h decreased with increasing chronological age (p<0.05). At common chronological age bands, late-maturing boys demonstrated superior RE than early-maturing boys from ages 10-14 years (p<0.05); average-maturing boys were also found to be more efficient than early-maturers at 12 and 13 years of age (p<0.05). Physical activity was not found to have any significant effect on the development of RE (p>0.05). A series of age-specific regression analyses identified body surface area and respiratory exchange ratio (RER) as variables which account for a significant portion of the variance in absolute VO2 (0.619<R^2<0.903); RER was not significant (p>0.05) at all chronological ages. Conclusion: Determining an appropriate approach for normalizing VO2 values is essential to allow for reliable investigation into factors other than size that affect RE. Maturity status was found to significantly affect RE development; however, only during the circumpubertal years. No effect of physical activity was found on RE development in boys 8-16 years. The relative influence of maturity status and RER are variable across different ages.

Previous reports have demonstrated that running economy (RE), a measure of efficiency of locomotion, is superior in adults than in children; however, it is unclear how these differences come to be. Purpose: To identify the effect of maturity status, physical activity and various other anatomical and physiological factors on RE development in boys aged 8 to 16 years. Methods: Data were collected as part of the Saskatchewan Growth and Development Study (SGDS; 1964-1973). Using a pure longitudinal study design, anthropometric, maturity, physiological characteristics (treadmill run) and physical activity were assessed annually for nine consecutive years. Two-hundred and two eight year-old males were measured in 1965; by 1973, complete longitudinal data were available for 63 participants. During the treadmill run, a measure of submaximal oxygen consumption (VO2) was recorded, an index of RE. Four approaches of normalizing VO2 to body size were investigated. Maturity status was determined based upon chronological age at peak height velocity (PHV). Physical activity was assessed by two teacher ratings and two questionnaires. Results: Normalizing VO2 to body surface area was found to be the most appropriate body size adjustment. Submaximal VO2 (ml/m^2/min) at 9.6 km/h decreased with increasing chronological age (p<0.05). At common chronological age bands, late-maturing boys demonstrated superior RE than early-maturing boys from ages 10-14 years (p<0.05); average-maturing boys were also found to be more efficient than early-maturers at 12 and 13 years of age (p<0.05). Physical activity was not found to have any significant effect on the development of RE (p>0.05). A series of age-specific regression analyses identified body surface area and respiratory exchange ratio (RER) as variables which account for a significant portion of the variance in absolute VO2 (0.619<R^2<0.903); RER was not significant (p>0.05) at all chronological ages. Conclusion: Determining an appropriate approach for normalizing VO2 values is essential to allow for reliable investigation into factors other than size that affect RE. Maturity status was found to significantly affect RE development; however, only during the circumpubertal years. No effect of physical activity was found on RE development in boys 8-16 years. The relative influence of maturity status and RER are variable across different ages.

Background: Running is one of the most popular branches of athletics. Running has several physiological benefits, such as a higher maximal oxygen consumption, increased muscle mass and reduced blood pressure. There have been plenty of discussions about what the most efficient running technique might be, should you use a short step length and a high step frequency or vice versa. It is generally known that you can increase your running speed by increasing your step frequency or your step length, and also both. However, maximal speed is achieved by increasing your step frequency rather than your step length. For endurance runners it is important to have a good running economy, because runners with a good running economy use less energy while running, and therefore require less oxygen than a runner with poor running economy. Previous research have not found any correlations between the length of the leg with step frequency or step length.  Aim: The aim of this study was to examine whether there are any significant correlations between the length of the leg in relation to the step frequency or the step length while running in different speeds.  Method: 15 trained males participated in this correlation study. All participants’ leg length were measured with a measuring tape. Three running trials, with the speeds of 12, 16 and 20 km/h were performed on a treadmill during 1 minute each. Between each trial the participants rested for 3 minutes. The trials were recorded with a video camera, and the participants individual step frequency, step length and heel or fore foot strike were collected. Persons coefficient of correlation test was used to analyze if there were any significant correlations between the length of the leg with step frequency and step length. Also a paired samples T test was performed to see if there was a significant increase between step frequency and step length with the speeds.  Result: There were no significant correlations (p&gt;0,05) found between the length of the leg and the step frequency or the length of the leg and step length in any of the different speeds. The paired samples t-test showed a significant (p&lt;0,001) increase in step frequency and step length with the different speeds.  Conclusion: In conclusion, according to the present study, there were no significant correlations found between the length of the leg with step frequency or step length, which is in consensus with previous research.  Therefore, it is not advisable to predict an individual’s step length based on their leg length. There are various factors involved in determining a person’s step length and step frequency, and this study showed that running speed is one important factor. This information may be useful for runners and their coaches to apply, so they avoid making interventions involving alternations in the runners step length based on their body dimensions, such as leg length.

Precooling, or a reduction in core temperature (Tc) has been demonstrated to be a potent enhancer of endurance running performance, however there is no known mechanism for this improvement. By holding the exercise workload constant, changes in variables such as running economy (RE), heart rate, and ventilation (VE) can be determined as a result of precooling. Improved running economy, or a reduced oxygen cost of a specific workload, is linked to improved exercise performance. Purpose: To determine the changes in flexibility, RE, heart rate, VE, and Tc during running at a constant workload following cool water immersion and to determine any sex-specific responses. Methods: Fourteen well-trained runners (8 males and 6 females) completed four treadmill runs at a sex-specific velocity (8.0 mph for females and 8.6 mph for males). The first two runs served as accommodation trials. The third and fourth runs were preceded by either cool water immersion (24.8oC) for 40 minutes or quiet sitting. Oxygen consumption, heart rate, Tc, VE, and flexibility were measured during both experimental trials. Results: Running economy did not change as a result of the precooling treatment, whereas Tc and heart rate were reduced by 0.4oC and 5 beats per minute, respectively. Minute ventilation was reduced in the female subjects only (1.4 liters/min). Sex differences were apparent in Tc, heart rate, VE, and flexibility response. Conclusion: While the precooling procedure was effective in reducing Tc and heart rate, RE did not change. Thus, improvements in RE cannot explain the dramatic enhancements of endurance running performance that often occur post-cooling. Differences between male and female subjects in response to precooling were identified, most notably in VE.

It has been shown that a high level of aerobic fitness is important for athletes participating in intermittent (team) sports. The majority of studies investigating the effects of traditional and sport-specific aerobic interval exercise on physiological measures and performance have involved field-based team sports. In some instances the effectiveness of sport-specific aerobic training has been questioned. To date, no study has investigated the influence of a sport-specific training approach in the sport of basketball. Purpose: The aim of the present study was to evaluate the effectiveness of a basketball specific endurance circuit on improving measures of aerobic fitness. Methods: Ten male high school basketball players, age 16.4 ± 1.2 years, ranked by fitness level and randomly assigned to a training group (N = 6) or control group (N = 4) participated in the study. The sport-specific aerobic endurance training replaced the fitness component of regular training and was performed during the competitive season. The sport-specific training consisted of interval training using a basketball specific endurance circuit, four times 4 min at 90-95% HRpeak with a 3 min recovery at 60-70% HRpeak, twice per week for 6 weeks. During this time the control group performed regular basketball training. Results: For both the training and control groups the actual mean training intensity for total training duration were 77.4 ± 2.9% HRpeak and 74.1 ± 6.7% HRpeak, respectively. The actual mean training intensity during the work intervals in the training group was 84.1 ± 2.3% HRpeak. There were no clear differences between effects of the two training approaches for measures of maximal oxygen uptake (3.3%; 90% confidence limits, ± 19.3%), running economy (-3.3%; 90% confidence limits, ± 14.2%), repeated sprint ability (0.6%; 90% confidence limits, ± 5.7%) and anaerobic power maintenance during the repeated sprints (-13.7%; 90% confidence limits, ± 49.0%). However, a clear non-trivial effect on sub-maximal heart rate was observed (-7.3%; 90% confidence limits, ± 2.0%) suggesting a beneficial training effect after training. Some evidence for attenuation of speed (-1.8 to -2.8%; 90% confidence limits, ± 3.4 to 5.7%) and power (-1.7%; 90% confidence limits, ± 17.1%) was apparent. Conclusion: Although clear changes in sub-maximal HR responses were observed in the training group, the data in the present study suggests that a basketball specific endurance circuit has little effect on other laboratory and field-based measures of aerobic fitness. In fact, the basketball specific endurance circuit may lead to reduced improvements in jumping and sprinting performances. Further research is required to clarify the effect of aerobic training approaches on basketball-specific fitness and performance.

It has been shown that a high level of aerobic fitness is important for athletes participating in intermittent (team) sports. The majority of studies investigating the effects of traditional and sport-specific aerobic interval exercise on physiological measures and performance have involved field-based team sports. In some instances the effectiveness of sport-specific aerobic training has been questioned. To date, no study has investigated the influence of a sport-specific training approach in the sport of basketball. Purpose: The aim of the present study was to evaluate the effectiveness of a basketball specific endurance circuit on improving measures of aerobic fitness. Methods: Ten male high school basketball players, age 16.4 ± 1.2 years, ranked by fitness level and randomly assigned to a training group (N = 6) or control group (N = 4) participated in the study. The sport-specific aerobic endurance training replaced the fitness component of regular training and was performed during the competitive season. The sport-specific training consisted of interval training using a basketball specific endurance circuit, four times 4 min at 90-95% HRpeak with a 3 min recovery at 60-70% HRpeak, twice per week for 6 weeks. During this time the control group performed regular basketball training. Results: For both the training and control groups the actual mean training intensity for total training duration were 77.4 ± 2.9% HRpeak and 74.1 ± 6.7% HRpeak, respectively. The actual mean training intensity during the work intervals in the training group was 84.1 ± 2.3% HRpeak. There were no clear differences between effects of the two training approaches for measures of maximal oxygen uptake (3.3%; 90% confidence limits, ± 19.3%), running economy (-3.3%; 90% confidence limits, ± 14.2%), repeated sprint ability (0.6%; 90% confidence limits, ± 5.7%) and anaerobic power maintenance during the repeated sprints (-13.7%; 90% confidence limits, ± 49.0%). However, a clear non-trivial effect on sub-maximal heart rate was observed (-7.3%; 90% confidence limits, ± 2.0%) suggesting a beneficial training effect after training. Some evidence for attenuation of speed (-1.8 to -2.8%; 90% confidence limits, ± 3.4 to 5.7%) and power (-1.7%; 90% confidence limits, ± 17.1%) was apparent. Conclusion: Although clear changes in sub-maximal HR responses were observed in the training group, the data in the present study suggests that a basketball specific endurance circuit has little effect on other laboratory and field-based measures of aerobic fitness. In fact, the basketball specific endurance circuit may lead to reduced improvements in jumping and sprinting performances. Further research is required to clarify the effect of aerobic training approaches on basketball-specific fitness and performance.

Running performance has increased immensely during the last few years, coinciding with multiple shattered world records in relatively short amount of time. Improvements in footwear material and design are likely reasons for this increase in running performance. Previous studies on the effect of footwear on running economy (RE), a determinant of running performance, have not included participant-blinding. Furthermore, they have yet to compare multiple carbon-fiber plated running shoes available for purchase, what differences there are across price ranges and shoe categories, and if there is such a thing as a placebo-effect. Aim: (1) Descriptively compare a set of heterogeneous running shoes, with regards to running economy, Foot Strike Type (FST), vertical oscillation, ground contact time, stride length and cadence; including (2) a ‘sham’ and ‘normal condition’ of the same running shoe model; and (3) explore the participant’s perception of the study-specific blinding protocol. Method: A Single Subject Experimental Study (N=1), comparing nine different shoe conditions using a crossover design. The assessment of RE was conducted using indirect calorimetry with mixing-chamber in a climate-controlled facility. Spatiotemporal parameters were assessed using a Garmin HRM-Run™, and foot strike type was visually assessed using a frame-by-frame approach based on 2D-video at 240 fps. Results: The average running economy across all shoe tests varied between 16.02 to 17.02 W/kg, with the ‘worst’ shoe costing 6.24% W/kg more than the ‘best’ shoe. The descriptive difference between the ‘sham’ and ‘normal condition’ were negligible and within the range of measurement error. Spatiotemporal parameters were overall descriptively similar between the shoes, with a few outliers who differed with regards to measure of central tendency or dispersion. FST differed between the shoes including the ‘sham’ and ‘normal condition’, but were overall consistent with the participant’s habitual FST. The study-specific blinding procedure was perceived to work well, but may also be improved in some remarks. Conclusion: Descriptive difference in some, but not all, physiological and biomechanical parameters were observed between the shoe conditions in this study, including the ‘sham’ and ‘normal condition’. Blinding procedures in experimental footwear research may be feasible and adopted with future studies.

Research surrounding the steeplechase is scarce, with most research focusing primarily on how biomechanical factors relate to maintaining running speed while crossing barriers. One area that has not been well explored is the relationship between biomechanical factors and hurdling economy. The purpose of this study was to investigate how performance times and biomechanical variables relate to hurdling economy during the steeplechase. This was accomplished by measuring running economy of collegiate and professional steeplechasers while running with and without hurdles. Biomechanical measures of approach velocity, take-off distance, clearance height, and lead knee extension while hurdling, as well as steeplechase performance times were correlated to a ratio of running economy with and without hurdles. Results indicated no correlation between steeplechase performance time and the ratio of running economy during the hurdle and non-hurdle laps. Results also indicated no correlation between the aforementioned biomechanical variables and ratio of running economy during the hurdle and non-hurdle laps. Increasing approach velocity did not negatively affect running economy. Steeplechasers may continue to increase approach velocity without hurting their economy or performance times.

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The objective of this dissertation was to evaluate the changes in preparedness over the course of training for a marathon in two well-trained runners. The athletes completed periodized strength training or a periodized concurrent training. This dissertation consisted of two separate investigations: Study 1 – The purpose of this study was to monitor changes in force production ability and running performance in one sub-elite marathon runner before, during, and after undertaking a short-term block periodized strength training program. The athlete ceased strength training during the off-seasons and resumed testing after 10. The athlete experienced likely true, meaningful changes in force production characteristics during the taper after the training program. Improvements in force production characteristics coincided with improvements in running economy. Both force production characteristics and running economy reversed after the withdraw from strength training. However, both measures remained improved from initial baseline. The improvement in running economy and force production likely coincided with a cardiovascular de-training period, due to a reduction in aerobic training during the off-season. Therefore, strength training may have independent effects on running economy and running performance. These results indicate that endurance runners may better optimize performance by improving force production characteristics via periodized strength training program, and should avoid prolonged periods without strength training. Study 2 – The purpose of this study was to monitor the concurrent and divergent changes in athlete preparedness and performance over a competitive training cycle in two marathon athletes. One athlete added a block periodized strength training program to a non-periodized endurance training program (NBP Athlete). The other athlete (BP Athlete) completed an integrated, concurrent block periodized program using HIT over-reach endurance training. Both athlete displayed improvements in running performance and running economy over the duration of the monitoring program. The BP Athlete displayed earlier and greater magnitudes of performance improvements. These results indicate that strength training can enhance running economy in marathon athletes, performance may be better optimized through periodized integration of strength and endurance training, and the use of HIT over-reach blocks may improve marathon relevant fitness characteristic within the ecologically valid context of an athlete’s training cycle.