Mixed active and passive, heart rate-controlled heat acclimation is effective for Paralympic and able-bodied triathletes

Purpose To explore the effectiveness of mixed, active and passive heat acclimation (HA), controlling the relative intensity of exercise by heart rate (HR) in paratriathletes (PARA) and determine adaptation differences to able-bodied (AB) triathletes.Methods Seven elite paratriathletes and thirteen AB triathletes undertook an 8-d HA intervention consisting of five HR-controlled sessions and three passive heat exposures (35oC, 63% relative humidity). On the first and last day of HA, heat stress tests were conducted whereby thermoregulatory changes were recorded during at a fixed, submaximal workload. The AB group undertook 20 km cycling time trials pre- and post-HA with performance compared to an AB, non-acclimated control group.Results During the heat stress test, HA lowered core temperature (PARA: 0.27 ± 0.32oC; AB: 0.28 ± 0.34oC), blood lactate concentration (PARA: 0.23 ± 0.15 mmol∙l-1; AB: 0.38 ± 0.31 mmol∙l-1) with concomitant plasma volume expansion (PARA: 12.7 ± 10.6; AB: 6.2 ± 7.7%) (p≤0.047). In the AB group, a lower skin temperature (0.19 ± 0.44oC) and HR (5 ± 6 bpm) with a greater sweat rate (0.17 ± 0.25 l∙h-1) was evident post-HA (p≤0.045) but this was not present for the PARA group (p≥0.177). The AB group improved their performance by an extent greater than the smallest worthwhile change based on the normal variation present with no HA (4.5 vs. 3.7%).Conclusions Paratriathletes are capable of displaying partial HA, albeit not to same extent as AB triathletes. The HA protocol was effective at stimulating thermoregulatory adaptations with performance changes noted in AB triathletes.</div

Physiology of handcycling: A current sports perspective

Handcycling is a mode of mobility, and sport format within Para-cycling, for those with a lower limb impairment. The exercise modality has been researched extensively in the rehabilitation setting. However, there is an emerging body of evidence detailing the physiological responses to handcycling in the competitive sport domain. Competitive handcyclists utilise equipment that is vastly disparate to that used for rehabilitation or recreation. Furthermore, the transferability of findings from early handcycling research to current international athletes regarding physiological profiles is severely limited. This narrative review aims to map the landscape within handcycling research and document the growing interest at the elite end of the exercise spectrum. From 58 experimental/case studies and four doctoral theses we: provide accounts of the aerobic capacity of handcyclists and the influence training status plays; present research regarding the physiological responses to handcycling performance, including tests of sprint performance; discuss the finite information on handcyclists’ training habits and efficacy of bespoke interventions. Furthermore, given the wide variety of protocols employed and participants recruited previously, we present considerations for the interpretation of existing research and recommendations for future work, all with a focus on competitive sport. The majority of studies (n=21) reported aerobic capacity, detailing peak rates of oxygen uptake and power output, with values >3.0 L∙min-1 and 240 W shown in trained, male H3-H4 classification athletes. Knowledge, though, is lacking for other classifications and female athletes. Similarly, little research is available concerning sprint performance with only one from eight studies recruiting athletes with an impairment

Physiological responses during simulated 16 km recumbent handcycling time trial and determinants of performance in trained handcyclists

Purpose: To characterise the physiological profiles of trained handcyclists, during recumbent handcycling, to describe the physiological responses during a 16 km time trial (TT) and to identify the determinants of this TT performance. Methods: Eleven male handcyclists performed a sub-maximal and maximal incremental exercise test in their recumbent handbike, attached to a Cyclus II ergometer. A physiological profile, including peak aerobic power output (POPeak), peak rate of oxygen uptake (V̇O2Peak), aerobic lactate threshold (AeLT) and PO at 4 mmol∙L-1 (PO4), were determined. Participants also completed a 16 km simulated TT using the same experimental set-up. Determinants of TT performance were identified using stepwise multiple linear regression analysis. Results: Mean values of POPeak = 252 ± 9 W, V̇O2Peak = 3.30 ± 0.36 L·min-1 (47.0 ± 6.8 mL·kg-1·min-1), AeLT = 87 ± 13 W and PO4 = 154 ± 14 W were recorded. The TT was completed in 29:21 ± 0:59 min:s at an intensity equivalent to 69 ± 4% POPeak and 87 ± 5% V̇O2Peak. POPeak (r = -0.77, P=0.006), PO4 (r = -0.77, P=0.006) and AeLT (r = -0.68, P=0.022) were significantly correlated with TT performance. PO4 and POPeak were identified as the best predictors of TT performance (r = 0.89, P Conclusion: POPeak, PO4 and AeLT are important physiological TT performance determinants in trained handcyclists, differentiating between superior and inferior performance whereas V̇O2peak was not. The TT took place at an intensity corresponding to 69% POPeak and 87% V̇O2peak.</p

Physiological correlates to in-race paratriathlon cycling performance

The purpose was to determine the physiological correlates to cycling performance within a competitive paratriathlon. Five wheelchair user and ten ambulant paratriathletes undertook laboratory-based testing to determine their: peak rate of oxygen uptake; blood lactate- and ventilatory-derived physiological thresholds; and, their maximal aerobic power. These variables were subsequently expressed in absolute (l∙min −1 or W), relative (ml∙kg−1∙min −1 or W∙kg −1) and scaled relative (or ml∙kg − 0.82 ∙min −1, ml∙kg − 0.32 ∙min −1 or W∙kg −0.32) terms. All athletes undertook a paratriathlon race with 20 km cycle. Pearson’s correlation test and linear regression analyses were produced between laboratory-derived variables and cycle performance to generate correlation coefficients (r), standard error of estimates and 95% confidence intervals. For wheelchair users, performance was most strongly correlated to relative aerobic lactate threshold (W∙kg −1) (r=−0.99; confidence intervals: −0.99 to −0.99; standard error of estimate=22 s). For ambulant paratriathletes, the greatest correlation was with maximal aerobic power (W∙kg −0.32) (r=−0.91; −0.99 to −0.69; standard error of estimate=88 s). Race-category-specificity exits regarding physiological correlates to cycling performance in a paratriathlon race with further differences between optimal scaling factors between paratriathletes. This suggests aerobic lactate threshold and maximal aerobic power are the pertinent variables to infer cycling performance for wheelchair users and ambulant paratriathletes, respectively.<br

The effect of pre-cooling or per-cooling in athletes with a spinal cord injury: a systematic review and meta-analysis

Objectives For individuals with a spinal cord injury (SCI), thermoregulatory challenges presented by the environment are amplified, increasing the risk of exertional heat illness. Thus, this systematic review and meta-analysis aims to quantify the effects of pre- and per-cooling on core temperature (Tc), skin temperature (Tsk) and thermal sensation in participants with SCI and assess the influence of lesion level on the effects of cooling. Design Systematic review with meta-analysis. Methods Out of 2107 potential studies, 17 were identified via the inclusion criteria for a total of 145 research participants. A total of 12 studies were included in the primary analysis of Tc; 9 included in the analysis of Tsk; and 9 included in the analysis of thermal perceptions. 15 experimental conditions were included in the secondary analysis of lesion level on the effects of cooling. Results Cooling reduced Tc (Hedges' g = 0.44; 95% confidence intervals [CI] 0.16, 0.72; p sk (Hedges' g = 1.11; 95% CI 0.56, 1.66; p c to a greater extent than per-cooling (Hedges' g = 0.25) (p = 0.020). The effect of lesion level on the effectiveness of cooling on Tc had a moderate, positive association (r = 0.518, p = 0.048). Conclusion Pre-cooling may reduce Tc to a greater extent than per-cooling during subsequent exercise. Pre-and per-cooling can attenuate the increase in thermal strain in athletes with an SCI. The beneficial effects of cooling are greater in tetraplegic individuals.</p

Ice slurry ingestion lowers thermoregulatory strain in wheelchair tennis players during repeated sprint intervals in the heat

Purpose: To examine the efficacy of per-cooling via ice slurry ingestion (ICE) in wheelchair tennis players exercising in the heat. Methods: Eight wheelchair tennis players undertook sprints (4 sets of 10 × 5 s over 40 min) in a hot environment (~32oC), interspersed by three boluses of 2.67 g∙kg (6.8 g∙kg total) ICE or drinking temperate water (CON). Athletes performed an on-court test of repeated sprint ability (20 × 20 m) in temperate conditions immediately before and 20 min after the heat exposure whereby time to complete each sprint, as well as intermediate times, was recorded. Gastrointestinal, weighted mean skin and forehead temperature were collected throughout the heat exposure, as were thermal sensation, heart rate and blood lactate concentration. Sweat rate was calculated from body mass changes and fluid/ice intakes. Results: Compared to CON, ICE resulted in a significantly lower gastrointestinal temperature (95% confidence intervals: 0.11, 0.17oC; p oC; p -1; p = 0.017). Skin temperature, heart rate and blood lactate concentration were not significantly different between conditions (p ≥ 0.598). There was no overall change pre- to post-heating (p ≥ 0.114) nor effect of condition (p ≥ 0.251) on repeated sprint times. Conclusions: ICE is effective at lowering objective and subjective thermal strain when consumed between sets of repeated wheelchair sprints in the heat. However, ICE had no effect on on-court repeated 20 m sprint performance.</p

Prehospital management of exertional heat stroke at sports competitions for Paralympic athletes

Objectives: To adapt key components of exertional heat stroke (EHS) prehospital management proposed by the International Olympic Committee (IOC) Adverse Weather Impact Expert Working Group for the Olympic Games Tokyo 2020 so that it is applicable for the Paralympic athletes.Methods: An expert working group representing members with research, clinical and lived sports experience from a Para sports perspective reviewed and revised the IOC consensus document of current best practice regarding the prehospital management of EHS.Results: Similar to Olympic competitions, Paralympic competitions are also scheduled under high environmental heat stress; thus, policies and procedures for EHS prehospital management should also be established and followed. For Olympic athletes, the basic principles of EHS prehospital care are: early recognition, early diagnosis, rapid, on-site cooling, and advanced clinical care. Although these principles also apply for Paralympic athletes, slight differences related to athlete physiology (e.g., autonomic dysfunction) and mechanisms for hands-on management (e.g., transferring the collapsed athlete or techniques for whole-body cooling) may require adaptation for care of the Paralympic athlete.Conclusions: Prehospital management of EHS in the Paralympic setting employs the same procedures as for Olympic athletes with some important alterations.</div