The relationship between critical power and running performance

Critical power is a theoretical concept that presumes there is a certain work‐rate which may be maintained without exhaustion. The extent to which critical power predicts running performance over varying distances has not been determined, and so the aim of this study was to correlate measurements of critical power in the laboratory to running performances in the field at 40 m and 1, 10 and 21.1 km in a group of 17 male longdistance runners (mean ± s.d. age = 31.7 ± 7.3 years). Each subject ran to exhaustion on the treadmill in the laboratory at six different speeds, ranging from 17 to 25 km h^‐1. Least squares analyses were used to fit an exponential decay to the relationship between the running speed (y) versus time to exhaustion (x). Critical power was calculated as the running speed (y) coinciding with the asymptote or C parameter of the y = A‐e^(‐Bx) + C relationship. The VO₂ max was also measured in all subjects. For the data in the field, each subject was timed over 40 m and 1 km and participated in 10‐ and 21.1‐km races. The mean critical power of die subjects in this study was 18.5 ± 1.6 km h^‐1. The test‐retest correlation coefficient for the determination of critical power was r = 0.99. The mean VO₂ max, measured in a progressive exercise protocol starting at 13 km h^‐1 and increasing by 1 km h^‐1 every minute, was 59.2 ± 4.6 ml O₂ kg^‐1 min^‐1. The 40‐m times ranged from 5.57 to 6.95 s, the 1‐km times from 2:46 to 3:55 min:s, the 10‐km times from 30:43 to 42:02 min:s and the 21‐km times from 67:00 to 95:45 min:s. Critical power predicted running times over 1 km (r = ‐0.75, P< 0.001), 10 km (r = ‐ 0.85, P< 0.00001) and 21.1 km (r = ‐ 0.79, P< 0.001) in this heterogeneous group of runners. The correlation coefficients for VO₂ max and running performances were similar to the above at all distances. Even in the best relationship between critical power and the time taken to run 10 km, only 72% of the variation in the 10‐km running time could be accounted for by differences in critical power. While the test of critical power may be repeatable and correlate significantly with VO₂ max (r = 0.77, P< 0.001), the measurement lacks the degree of specificity required to predict running performance in trained subjects of varying ability.     

Self-Efficacy for Coping With Barriers Helps Students Stay Physically Active During Transition to Their First Year at a University

The present study examined undergraduate students' physical activity during transition from high school to first-year university. Students' (N = 127) self-efficacy for coping with barriers to physical activity was investigated both as a predictor of physical activity and mediator of the relationship between pretransition and first-year physical activity. Physical activity was found to track moderately from pretransition to first year (r _s = .58). Self-efficacy for coping with barriers predicted physical activity (R ² _adjusted = .18, p < .05) and partially mediated the relationship between pretransition and first-year physical activity. Results support an interpretation that future intervention efforts could target first-year students' self-efficacy for coping with barriers to help curb the decline in physical activity that occurs during the transition to university life.     

A transition model for placement of handicapped children in regular and special classes

Mainstreaming and deinstitutionalization are current phenomena which call for a variety of handicapped children to be transitioned to a range of educational settings not previously available to them. A model is presented in which critical transition parameters are conceived as functionally related continua, indicating degrees of readiness for both special and regular classroom settings. The model is based upon actual experience in placement of disturbed, learning disabled, and retarded children into school settings after discharge from a psychiatric hospital.     

Ground zero: The information war in the Persian Gulf

This article provides an overview for the symposium while delving into specific facts about the development and implementation of the Pentagon's press policy during the Persian Gulf War. The article assesses the military-media relationship, and the Pentagon's own policy development, in the aftermath of the invasions of Grenada and Panama. It describes the power and authority of the President, and civilian and military leaders, at the time of the war, to supersede the best intentions and plans of Pentagon public affairs specialists. It reveals the inability of the media during war to perceive and impact how such policy is shaped. The article identifies, as a high priority, the independent, timely, and accurate reporting to the nation when America enters combat.     

Effects of knowledge of semantic roles on summarizing written prose

College students wrote summaries of eight short passages as a test of their ability to identify important information. After pairing naive summaries according to length and original passage, those summaries which judges identified as “better” were found to contain significantly more of the major semantic roles, such as Agent and Instrument, than did summaries judged “not as good.” It was also found that students wrote significantly better summaries when instructed to base the summaries on the major semantic roles within the passage. These summaries were significantly better than summaries based upon the traditional paragraph analysis of “topics” and “main ideas,” and they were significantly better than summaries written without any special instructions.     

Time-motion analysis of elite field hockey, with special reference to repeated-sprint activity

Limited information exists about the movement patterns of field-hockey players, especially during elite competition. Time-motion analysis was used to document the movement patterns during an international field-hockey game. In addition, the movement patterns of repeated-sprint activity were investigated, as repeated-sprint ability is considered to be an important fitness component of team-sport performance. Fourteen members of the Australian men's field-hockey team (age 26+/-3 years, body mass 76.7+/-5.6 kg, VO2max 57.9+/-3.6 ml.kg(-1).min(-1); mean+/-s) were filmed during an international game and their movement patterns were analysed. The majority of the total player game time was spent in the low-intensity motions of walking, jogging and standing (46.5+/-8.1, 40.5+/-7.0 and 7.4+/-0.9%, respectively). In comparison, the proportions of time spent in striding and sprinting were 4.1+/-1.1 and 1.5+/-0.6%, respectively. Our criteria for 'repeated-sprint' activity (defined as a minimum of three sprints, with mean recovery duration between sprints of less than 21 s) was met on 17 occasions during the game (total for all players), with a mean 4+/-1 sprints per bout. On average, 95% of the recovery during the repeated-sprint bouts was of an active nature. In summary, the results suggest that the motion activities of an elite field-hockey competition are similar to those of elite soccer, rugby and Australian Rules football. In addition, the investigation of repeated-sprint activity during competition has provided additional information about the unique physiological demands of elite field-hockey performance.