Physiological Responses to Maximal Treadmill and Handweighted Exercise

Abstract

The purpose of this investigation was to compare the peak physiological responses among four protocols that employed different amounts of handweighted exercise in 16 males (aged 26.3 ± 4.1 years). The four protocols were (a) uphill treadmill running (UR; 3.36 m-s¹, 2.5% grade increase-3 min¹); (b) uphill treadmill walking while pumping 1.36kg handweights (HW) (UWHW; 1.79ms¹, 5.0% grade increase-3 min¹; (c) treadmill walking while pumping .91-kg HW (WHW; 1.79 m-s¹, 0% grade, .91kg HW increase-3 min¹); and (d) standing in place and pumping HW (SHW; arm work as described in WHW). It was hypothesized that the peak responses would be inversely proportional to the estimated muscle mass activated (i.e., UR = UWHW > WHW > SHW). Dependent variables included peak oxygen uptake (VO₂ peak), peak heart rate (HRpeak), peak ventilation (V_epeak), and peak respiratory exchange ratio (RERpeak). No differences were noted between UR and UWHW with respect to any of the dependent variables. All variables (except RERpeak) were greater (p < .01) in UR and UWHW than either WHW or SHW. RERpeak was greater (p < .01) in UR and UWHW than in WHW. VO₂peak and HRpeak were greater (p < .01) in WHW when compared to SHW. Mean VO₂peak was 97.5, 69.7, and 60% of UR for UWHW, WHW, and SHW, respectively. Therefore, walking and pumping handweights provides a maximal stimulus to the oxygen transport system.     

Striving to Be in the Profession and of It

Abstract

This study analyzes the experiences of African Americans in the physical education and kinesiology profession since the late 1850s. Using a variety of primary and secondary source material, we place special emphasis on the experiences of African American physical educators in higher education and in the American Alliance for Health, Physical Education, Recreation and Dance and its southern, regional, and state chapters. Apparent from this examination is that African Americans have experienced various forms of racially discriminatory practices in physical education and kinesiology and have found it extraordinarily difficult to assume leadership positions in the profession and be acknowledged for their scholarly and academic accomplishments.     

Urea production during prolonged swimming

Male interscholastic swimmers (n = 8) completed a 4572 m training swim in 62 ±1.1 min (x ± s.e.) with terminal heart rate and blood lactate of 152 ± 6 beats min^‐1 and 6.9±0.89 mM, respectively. Sweat rate (0.48±0.0951. h^‐1) was lower than similar intensity cycling (1.5±0.13 1. h^‐1) or running (1.1 ± 0.14 l.h^‐1). Post‐swim serum urea N (11.6±0.71 mM) was elevated (P<0.05) vs pre‐swim (4.6±0.39 mM). Post‐swim urine volume (860±75 ml 24 h^‐1) was reduced (P<0.07) and resulted in an elevated (P<0.05), but delayed (24–84 h), post‐exercise urea N excretion. Although the reduced urine and sweat production during the swim undoubtedly contributed to the elevated serum urea, there must be another explanation because together they could only account for 38% of the observed increase. On the basis of the magnitude of serum urea increase, it appears that the swim caused an increase in urea production (amino acid oxidation). The failure to observe larger increases in urinary urea during recovery indicates that either urea excretion following exercise continues for prolonged periods of time (>48 h) or another significant mode of nitrogen excretion exists.     

Sport and the sociologist 1890–1914

This essay is a response to Paul Ward’s piece ‘Last Man Picked. Do Mainstream Historians Need to Play with Sports Historians?’ (The International Journal of the History of Sport (2012), doi:10.1080/09523367.2012.726617). While Ward admits that his work is a polemic and is inspired largely by events in his youth, this response nevertheless questions the decision to critique an entire sub-discipline based on childhood experiences. Ward’s criticisms, however, are also practice-based, and this response also critically examines the lack of fresh evidence to support Ward’s claims regarding sports history’s existence outwith mainstream historical academia, and its supposed privileged place within the wider world of leisure history. The author makes that case that not only does sports history to take part in a wider historical dialogue, but must necessarily look to engage with sports studies practitioners. Finally, in the face of Ward’s criticisms, this essay reiterates what makes sport a vital subject for historians, in regional, national and international contexts.     

Characteristics of the start in women's World Cup skeleton

This study characterizes key elements of the start in elite female World Cup skeleton athletes. The top 20 female competitors in three World Cup races were videotaped within a calibrated space to allow the following components of the start to be quantified: (1) acceleration (velocity at 15-m mark, time to 15-m mark), (2) capacity (time to load, total number of steps to load), and (3) load (velocity at 45-m mark). A correlation analysis was used to establish the relationship between the variables of interest and overall start time (15- to 65-m mark). Velocity at the 15-m mark accounted for 86% of the variance in overall start time at St. Moritz and 85% at Sigulda. A stepwise regression analysis revealed that approximately 89% of the variation in start time could be explained by velocity at the 15-m mark, time to load, and velocity at the 45-m mark. Of the variables analysed in this study, rapid acceleration to attain a high velocity at the 15-m mark was the most important component of a fast overall start time. The importance of the time to load and velocity at the 45-m mark vary according to the different track characteristics.     

Acute effects of intense interval training on running mechanics

The aims of this study were to determine if there are significant kinematic changes in running pattern after intense interval workouts, whether duration of recovery affects running kinematics, and whether changes in running economy are related to changes in running kinematics. Seven highly trained male endurance runners (VO 2max = 72.3 +/- 3.3 ml kg -1 min -1 ; mean +/- s) performed three interval running workouts of 10 X 400 m at a speed of 5.94 +/- 0.19 m s -1 (356 +/- 11.2 m min -1 ) with a minimum of 4 days recovery between runs. Recovery of 60, 120 or 180 s between each 400 m repetition was assigned at random. Before and after each workout, running economy and several kinematic variables were measured at speeds of 3.33 and 4.47 m s -1 (200 and 268 m min -1 ). Speed was found to have a significant effect on shank angle, knee velocity and stride length (P ? 0.05). Correlations between changes pre- and post-test for VO 2 (ml kg -1 min -1 ) and several kinematic variables were not significant (P > 0.05) at both speeds. In general, duration of recovery was not found to adversely affect running economy or the kinematic variables assessed, possibly because of intra-individual adaptations to fatigue.     

A Multidimensional Timing Device for Cinematography

Abstract

Six tests were developed for the purpose of measuring selected basic skills in ice hockey. The test-retest method indicated four tests as reliable. Validity coefficients for each of the four tests when compared to subjective ranking in each skill ranged from .75 to .96. Intercorrelations were computed among the tests. The puck carry test correlated with the other three tests and was determined the best single-item for measuring overall ability. It was concluded that an ice hockey test battery should include at least three of the tests.     

Force-Time Curves of Voluntary Muscular Contraction at Varying Tensions

Abstract

A recording spring-loaded hand ergograph with fast moving paper was utilized to obtain a record of the entire hand contraction sequence. The subjects (N=40) were given a series of six contractions, each beginning at a different initial tension: 0, 10, 15, 20, 25, and 30 kilograms. The contractions were separated by one minute and the order was systematically rotated to minimize either learning or fatigue. The development of force was found to progress exponentially according to a three-component mathematical equation. The control group (zero pre-tension) achieved a greater maximal force (F=4.5) than all others, and was the only one with a clear advantage in speed and tension. The rate of change constants were comparable, but the early initial (negative) component disappeared at the 20 kilogram condition and beyond. The factor of rate seemed to be independent of tension level.     

The Relationship between Perceptual and Motor Abilities

Abstract

Eighty randomly selected kindergarten pupils were administered one of four figure-ground variations of a gross motor task in order to determine the effects of the various patterns on the performance of the task. All subjects were administered the figure-ground subtest of the Frostig Developmental Test of Visual Perception and the gross motor task which involved walking in a lateral direction between the rungs of a ladder placed in a horizontal position over a floor pattern. An analysis of variance revealed significant differences in the error-time performance among the groups. Pearson product-moment correlation techniques revealed significant relationships between the gross motor task and the Frostig test.     

Rotation,Translation, and Trajectory in Diving

Abstract

Theories causing rotation of the body in diving were critically reviewed and a statement relating angular momentum to both the angle of lean and the angle of force was presented. Equations were developed by which the partition of energy between rotation and translation could be computed.