Effects of mild heat exposure on fatigue responses during two sets of repeated sprints matched for initial mechanical output

OBJECTIVES

We examined whether mild heat exposure alters performance, perceptual responses and neural drive to the quadriceps during two sets of repeated sprints matched for initial mechanical output.

DESIGN

Repeated measures.

METHODS

Twelve males performed 10 × 6-s sprints (recovery = 30 s), followed 6 min later by 5 × 6-s sprints (recovery = 30 s) in either COOL (24 °C/30% rH) or HOT (35 °C/40% rH) conditions. Subsequently, two sets of five consecutive sprints matched for initial mechanical output were compared.

RESULTS

On the basis of peak power, performance in sprint 2 was not significantly different to sprint 11 in both conditions (p ≥ 0.32). Average peak power across the five sprints compared (i.e., sprints 2-6 and 11-15, respectively) was 2.6 ± 3.4% higher in HOT compared to COOL (p = 0.025). Electromyographic activity (root mean square value) of the vastus lateralis muscle remained unchanged. Core (sprints 2-6: 37.85 ± 0.21 vs. 37.53 ± 0.19 °C, sprints 11-15: 38.26 ± 0.33 vs. 37.89 ± 0.24 °C; p < 0.001) and skin (sprints 2-6: 36.21 ± 0.29 vs. 30.72 ± 0.52 °C, sprints 11-15: 36.37 ± 0.28 vs. 30.99 ± 0.55 °C; p < 0.001) temperatures were overall higher in HOT compared to COOL. Heart rate, thermal sensation and comfort were significantly elevated in HOT compared to COOL (p ≤ 0.02), irrespective of sprint number.

CONCLUSIONS

When two sets of repeated sprints were matched for initial mechanical output, performance was enhanced with mild heat exposure. This occurred despite higher thermal, cardiovascular, and perceptual strain, and without alterations in quadriceps neural drive.

Neuromuscular and perceptual responses during repeated cycling sprints-usefulness of a "hypoxic to normoxic" recovery approach

PURPOSE

We investigated the consequence of varying hypoxia severity during an initial set of repeated cycling sprints on performance, neuromuscular fatigability, and exercise-related sensations during a subsequent set of repeated sprints in normoxia.

METHODS

Nine active males performed ten 4-s sprints (recovery = 30 s) at sea level (SL; FiO₂ ~ 0.21), moderate (MH; FiO₂ ~ 0.17) or severe normobaric hypoxia (SH; FiO₂ ~ 0.13). This was followed, after 8 min of passive recovery, by five 4-s sprints (recovery = 30 s) in normoxia.

RESULTS

Mean power decrement during Sprint 10 was exacerbated in SH compared to SL and MH (- 34 ± 12%, - 22 ± 13%, - 25 ± 14%, respectively, p < 0.05). Sprint performance during Sprint 11 recovered to that of Sprint 1 in all conditions (p = 0.267). All exercise-related sensations at Sprint 11 recovered significantly compared to Sprint 1, with no difference for Set 2 (p > 0.05). Ratings of overall perceived discomfort, difficulty breathing, and limb discomfort were exacerbated during Set 1 in SH versus SL (p < 0.05). Compared to SL, the averaged MPO value for Set 2 was 5.5 ± 3.0% (p = 0.003) lower in SH. Maximal voluntary force and twitch torque decreased similarly in all conditions immediately after Set 1 (p < 0.05), without further alterations after Set 2. Peripheral and cortical voluntary activation values did not change (p > 0.05).

CONCLUSION

Exercise-related sensations, rather than neuromuscular function integrity, may play a pivotal role in influencing performance of repeated sprints and its recovery.

Patient preferences for timing and access to radiation therapy

PURPOSE

Patient preferences for radiation therapy (rt) access were investigated.

METHODS

Patients completing a course of rt at 6 centres received a 17-item survey that rated preferences for time of day; day of week; actual, ideal, and reasonable travel times for rt; and actual, ideal, and reasonable times between referral and first oncologic consultation. Patients receiving single-fraction rt or brachytherapy alone were excluded.

RESULTS

Of the respondents who returned surveys (n = 1053), 54% were women, and 74% had received more than 15 rt fractions. With respect to appointment times, 88% agreed or strongly agreed that rt between 08h00 and 16h30 was preferred; 14%-15% preferred 07h30-08h00 or 16h30-17h00; 10% preferred 17h00-18h00; and 6% or fewer preferred times before 07h30 or after 18h00. A preference not to receive rt before 07h30 or after 18h00 was expressed by 30% or more of the respondents. When days of the week were considered, 18% and 11% would have preferred to receive rt on a Saturday or Sunday respectively; 52% and 55% would have preferred not to receive rt on those days. A travel time of 1 hour or less for rt was reported by 82%, but 61% felt that a travel time of 1 hour or more was reasonable. A first consultation within 2 weeks of referral was felt to be ideal or reasonable by 88% and 73% of patients respectively.

CONCLUSIONS

An rt service designed to meet patient preferences would make most capacity available between 08h00 and 16h30 on weekdays and provide 10%-20% of rt capacity on weekends and during 07h30-08h00 and 16h30-18h00 on weekdays. Approximately 80%, but not all, of the responding patients preferred a 2-week or shorter interval between referral and first oncologic consultation.

Responses of PROP taster groups to variations in sensory qualities within foods and beverages

Despite increasing evidence that variations in sensitivity to the bitterness of 6-n-propylthiouracil (PROP) are also reflected in responses to other tastes in solution, there has been little research examining the impact of PROP sensitivity on responses to sensory qualities in foods or beverages. The present studies examined responses of PROP taster groups to systematic variations in tastes and oral irritation in different foods and beverages. In Experiment 1, PROP groups were asked to discriminate variations in bitterness, sweetness, or sourness within two foods (yogurt and cream cheese) and a beverage (orange juice). In most cases, tasters and especially supertasters (STs) were able to discriminate smaller variations in tastant concentration than PROP nontasters (NTs). Differences were most evident with variations in bitterness and sourness. In Experiment 2, PROP taster groups rated the sweetness, sourness, and oral irritation in carbonated fruit drinks that systematically varied in citric acid (CA) and CO2 concentrations. Ratings of sourness and irritation were highest for STs and lowest for NTs, although there were no group differences for sweetness ratings. These data are some of the first to show PROP taster group differences in tastes and irritation within foods and provide a basis for reported differences of PROP groups in their hedonic responses to foods.

The King's College Hospital Acute Stroke Unit

The King's College Hospital (KCH) Acute Stroke Unit (ASU) was set up in January 1994 in order to provide acute management for patients admitted with stroke and to undertake biomedical research. Of 206 patients admitted to KCH with a stroke or suffering an in-hospital stroke, 141 (68%) patients were admitted to the ASU over its first 6 months of operation: 120 (85%) were from the Accident and Emergency Department and 21 (15%) from other wards. Management included resuscitation and medical stabilisation, investigation, prevention of stroke complications (including aspiration, venous thrombosis, and pressure sores), rehabilitation (physiotherapy, occupational therapy, speech and language therapy), nutrition (dietetics) and initiation of secondary prevention measures (aspirin or anticoagulation, blood pressure and lipid lowering, and carotid endarterectomy). All aspects of management are driven by agreed guidelines. Patients remain under the care of the admitting physician but specific stroke management and guidance is provided by two research doctors and the unit's nurses, therapists and dietician. The unit also facilitates research into stroke pathophysiology and acute therapeutic interventions. Our experience suggests that an ASU is relatively easy to set up and may contribute to improved care. Whether ASUs improve patient survival and functional outcome, and are cost-effective, requires further study.

Comparison of parent-referred and doctor-referred patients to child psychiatrists in Hong Kong: a research note

The characteristics of 75 children referred to psychiatrists by medical practitioners in Hong Kong were compared with 56 children who were referred by their families to a community clinic. Their demographic characteristics, and the nature and severity of their illness, were quite similar. Medical practitioners tended to refer children with childhood psychosis and psychophysiological disorder. The reasons leading to different types of referral are discussed. A community child mental health clinic may be a useful model for providing psychiatric care to children in Hong Kong.