Surfing Time-Motion Characteristics Possible to Gain Using Global Navigation Satellite Systems: A Systematic Review.

The popularity of surfing has increased exponentially, reaching its recent debut in the Olympic Games. However, surfing suffers from a relative immature technological market, while in other sports some technologies such as global navigation satellite systems (GNSSs) have become an essential work material for strength and conditioning and head coaches. This article aims to systematically review surfers' time-motion demands based on GNSSs. A systematic review of relevant articles was carried out using five main databases (PubMed, ProQuest Central, SCOPUS, SPORTDiscus, and FECYT (Web of Sciences, CCC, CIDW, KJD, MEDLINE, RSCI, and SCIELO)) until 23 March 2024. From the 238 studies initially found, 9 were included in the qualitative synthesis. In these, GNSS devices were employed with male (n = 143) and female (n = 28) surfers from different levels during competition and training situations. The studies show that the intermittent nature of the sport is evident, with substantial periods spent paddling and waiting punctuated by relatively brief high-intensity efforts when riding waves at high speeds. Notable differences emerged between competition and training demands, suggesting potential mismatches in how athletes currently prepare compared to event requirements. These novel insights allow quantifying surfing's harsh physiological requirements and could guide conditioning practices to better meet the sport's unique characteristics across populations. Therefore, training should emulate the lengthy aerobic capabilities needed for the paddling volumes observed, while also targeting the anaerobic systems to meet the repeated high-intensity surf riding efforts. However, inconsistencies in methods and reporting practices limit direct comparisons and comprehensive profiling of the sport's physical characteristics.

Physiological stress in flat and uphill walking with different backpack loads in professional mountain rescue crews.

This study aimed to determine the interactive physiological effect of backpack load carriage and slope during walking in professional mountain rescuers. Sixteen mountain rescuers walked on a treadmill at 3.6 km/h for 5 min in each combination of three slopes (1%, 10%, 20%) and five backpack loads (0%, 10%, 20%, 30%, and 40% body weight). Relative heart rate (%HRmax), relative oxygen consumption (%VO2max), and rating of perceived exertion (RPE, Borg 1-10 scale) were compared across conditions using two-way ANOVA. Significant differences in %VO2max, %HRmax, and RPE across slopes and loads were found where burden increased directly with slope and load (main effect of slope, p < 0.001 for all; main effect of load, p < 0.001 for all). Additionally, significant slope by load interactions were found for all parameters, indicating an additive effect (p < 0.001 for all). Mountain rescuers should consider the physiological interaction between slope and load when determining safe occupational walking capacity.

Changes in the Second Ventilatory Threshold Following Individualised versus Standardised Exercise Prescription among Physically Inactive Adults: A Randomised Trial.

The second ventilatory threshold (VT2) is established as an important indicator of exercise intensity tolerance. A higher VT2 allows for greater duration of higher intensity exercise participation and subsequently greater reductions in cardiovascular disease (CVD) risk. This study aimed to compare the efficacy of standardised and individualised exercise prescription on VT2 among physically inactive adults. Forty-nine physically inactive male and female participants (48.6 ± 11.5 years) were recruited and randomised into a 12-week standardised (n = 25) or individualised (n = 24) exercise prescription intervention. The exercise intensity for the standardised and individualised groups was prescribed as a percentage of heart rate reserve (HRR) or relative to the first ventilatory threshold (VT1) and VT2, respectively. Participants were required to complete a maximal graded exercise test at pre-and post-intervention to determine VT1 and VT2. Participants were categorised as responders to the intervention if an absolute VT2 change of at least 1.9% was attained. Thirty-eight participants were included in the analysis. A significant difference in VT2 change was found between individualised (pre vs. post: 70.6% vs. 78.7% maximum oxygen uptake (VO2max)) and standardised (pre vs. post: 72.5% vs. 72.3% VO2max) exercise groups. Individualised exercise prescription was significantly more efficacious (p = 0.04) in eliciting a positive response in VT2 (15/19, 79%) when compared to the standardised exercise group (9/19, 47%). Individualised exercise prescription appears to be more efficacious than standardised exercise prescription in eliciting a positive VT2 change among physically inactive adults. Increasing VT2 allows for greater tolerance to higher exercise intensities and therefore greater cardiovascular health outcomes.

Physiological Response Differences between Run and Cycle High Intensity Interval Training Program in Recreational Middle Age Female Runners.

The aim of this investigation was to compare the changes in endurance running performance and physiological variables after a four-week period of high intensity interval training (HIIT) in either running or cycling in female athletes. Fourteen recreational female runners (age = 42 10 yr, height = 1.67 0.06 m, body mass = 61.6 10.4 kg, body mass index (BMI) = 22.2 3.4 kg.m-2) were randomly allocated to one of two HIIT training groups: running (HIITrun) or cycling (HIITbike). Each group performed two HIIT sessions per week for 4 weeks, which consisted of 6 x 2 min at 95% of maximal heart rate (HRmax) and 4 x 1 min all out efforts. Maximal oxygen consumption (VO2max) in treadmill running increased significantly after the HIITrun (p < 0.01, ES = 0.6) but remained unchanged in HIITbike. However, HIITbike improved average velocity in a 10 km running time trial (TTrun) (p < 0.05, ES = -0.4), whereas, no changes were found for the HIITrun group. Analysing the first and last HIIT sessions, for HIITrun only the average rate of perceived exertion (RPEav) increased significantly, whereas, performance variables such as average heart rate (HRav) and average pace (paceav) remained unchanged. HIITbike enhanced significantly the average speed of HIIT sets (speedav) and the peak power output (PPO) of the session, as well as, the RPEav and delayed onset muscle soreness immediately after HIIT session (DOMSpost) were increased significantly. A regime of HIIT in cycling may evoke increases in female recreational runners' power, which may be related with improvements in a 10 km TTrun independent of changes in aerobic capacity. This may be advantageous in order to avoid overuse running related injuries.

A Contemporary Variable-Power Cycling Protocol to Discriminate Race-Specific Performance Ability.

PURPOSE: Traditional physiological testing and monitoring tools have restricted our ability to capture parameters that best relate to cycling performance under variable-intensity race demands. This study examined the validity of a 1-h variable cycling test (VCT) to discriminate between different-performance-level cyclists. METHODS: Ten male national- and 13 club-level cyclists (body mass, 67 [9] and 79 [6] kg; peak power output, 359 [43] and 362 [21] W, respectively) completed a VO2max test and two 1-h VCT protocols on 3 separate occasions. The VCT consisted of 10 × 6-min segments containing prescribed (3.5 W·kg-1) and open-ended phases. The open-ended phases consisted of 4 × 30-40 s of "recovery," 3 × 10 s at "hard" intensity, and 3 × 6-s "sprint" with a final 10-s "all-out" effort. RESULTS: Power output for the 6- and 10-s phases was moderately higher for the national- compared with club-level cyclists (mean [SD] 10.4 [2.0] vs 8.6 [1.6] W·kg-1, effect size; ±90% confidence limits = -0.87; ±0.65 and mean [SD] 7.5 [0.7] vs 6.2 [1.0] W·kg-1, effect size; ±90% confidence limits = -1.24; ±0.66, respectively). Power output for the final 10-s "all-out" sprint was 15.4 (1.5) for the national- versus 13.2 (1.9) W·kg-1 for club-level cyclists. CONCLUSION: The 1-h VCT can successfully differentiate repeat high-intensity effort performance between higher-caliber cyclists and their lower-performing counterparts.

Comparison of Reduced-Volume High-Intensity Interval Training and High-Volume Training on Endurance Performance in Triathletes.

PURPOSE: To investigate changes in physiological and performance variables in triathletes following a 4-wk period of reduced training volume and increased training intensity. METHODS: Sixteen moderately trained triathletes were randomly allocated to 2 groups: a control (CON) group, which followed their usual training, or a high-intensity interval training (HIIT) group, which completed 2 HIIT sessions per week during 4 wk of reduced training volume Results: Maximal oxygen consumption (VO2max) increased significantly in the HIIT group (P = .03, d = 0.5) but remained unchanged in the CON group. Cycling power at first and second ventilatory thresholds increased significantly in the HIIT subjects (P = .03, d = 1.0) and was unchanged in the CON participants (P = .57). During the simulated triathlon test, pretest-posttest cycling times and average power were unchanged in both groups (P > .05). No significant interactive effects between groups were observed for running time (P = .50). CONCLUSION: After a 4-wk HIIT program, VO2max and power at first and second ventilatory thresholds were found to have increased significantly while cycling and running performance were unchanged, despite an overall reduction in training time. In the present study, performance was only shown to improve with usual (high-volume) training. Summarizing, in order to improve running or cycling performances, high-volume training programs are highly recommended.

The effect of ice slurry ingestion on body temperature and cycling performance in competitive athletes.

The effects of pre cooling on endurance performance are widely known. In contrast, the approach of cooling during endurance exercise in combination with pre-exercise cooling has been poorly understood. The purpose of the present study was to determine whether the effects of precooling and cooling during exercise enhance exercise performance compared to the ingestion of a thermo-neutral beverage (20 °C) or precooling alone in cycling performance. This was an experimental study using a randomised crossover design in which 7 cyclists underwent three trials comprising of 45 min steady state cycling (SS) at 70% VO2 max and a subsequent 10 km time trial (TT) in hot conditions (32 °C, 50% relative humidity). Rectal temperature (Tre), heat storage (HS), heart rate (HR), blood lactate concentration (BLA) and thermal sensation (TS) were measured. The intervention consisted of: (1) ingestion of thermo-neutral beverage before and during SS cycling (TN), (2) ingestion of ice slurry beverage and application of iced towels (precooling) prior to exercise, and then ingestion of thermo-neutral beverage during SS (PRE) and (3) precooling strategy as above plus ice slurry ingestion during SS cycling (PRE + MID). The intake of thermo-neutral or ice slurry beverage (14 g/kg) occurred over 30 min before and every 15 min during SS cycling. There was no significant difference in TT performance between all the conditions (P =0.72). However, PRE and PRE + MID caused a significant decrease in Tre (P < 0.05) from TN during exercise. Accordingly, both precooling and a combination of precooling and mid-cooling during exercise in hot conditions may be a practical and effective way of reducing core temperature. Future studies should investigate longer distance events and timing of ice slurry ingestion.

Cerebral hemodynamics during graded Valsalva maneuvers.

The Valsalva maneuver (VM) produces large and abrupt changes in mean arterial pressure (MAP) that challenge cerebral blood flow and oxygenation. We examined the effect of VM intensity on middle cerebral artery blood velocity (MCAv) and cortical oxygenation responses during (phases I-III) and following (phase IV) a VM. Healthy participants (n = 20 mean ± SD: 27 ± 7 years) completed 30 and 90% of their maximal VM mouth pressure for 10 s (order randomized) whilst standing. Beat-to-beat MCAv, cerebral oxygenation (NIRS) and MAP across the different phases of the VM are reported as the difference from standing baseline. There were significant interaction (phase (*) intensity) effects for MCAv, total oxygenation index (TOI) and MAP (all P < 0.01). MCAv decreased during phases II and III (P < 0.01), with the greatest decrease during phase III (-5 ± 8 and -19 ± 15 cm·s(-1) for 30 and 90% VM, respectively). This pattern was also evident in TOI (phase III: -1 ± 1 and -5 ± 4%, both P < 0.05). Phase IV increased MCAv (22 ± 15 and 34 ± 23 cm·s(-1)), MAP (15 ± 14 and 24 ± 17 mm Hg) and TOI (5 ± 6 and 7 ± 5%) relative to baseline (all P < 0.05). Cerebral autoregulation, indexed, as the %MCAv/%MAP ratio, showed a phase effect only (P < 0.001), with the least regulation during phase IV (2.4 ± 3.0 and 3.2 ± 2.9). These data illustrate that an intense VM profoundly affects cerebral hemodynamics, with a reactive hyperemia occurring during phase IV following modest ischemia during phases II and III.

Hematological changes in an elite climber over 18 years.

AIMS: To evaluate the influence of repeated exposure to high altitude over a period of 18 years in an elite climber, red blood cell related parameters were analyzed. Red blood cell levels, hemoglobin concentration, and hematocrit were taken before and after expedition. RESULTS: The analysis, revealed an average increase of 15% in red blood cell related parameters, and showed a negative correlation (p<0.01) between age and post-expedition results. Furthermore, the first part of the study period was statistically different compared to the second (p<0.01). CONCLUSION: Exposure to extreme altitudes does lead to an increase in red blood cell parameters in the subject of the present study, as it can be seen from the results. Interestingly, this hematological response to extreme hypobaric hypoxia stimuli was attenuated over time. This however is a case report on an elite climber, and further research is needed in order to determine if such responses can be observed in other populations.

The effect of patellar taping on some landing characteristics during counter movement jumps in healthy subjects.

The aim of the present study was to determine the effect of patellar taping (PT) on landing characteristics of the vertical ground reaction force (VGRF) and on flight time during a counter movement jump (CMJ). Eleven healthy male subjects (age: 31.1 ± 4.2 years) volunteered for the study. Each subject performed six CMJs under two different jumping conditions: with PT and without PT (WPT). The order of the two conditions was randomized. All of the measured variables had fair-to-good reliability (intra-class correlation coefficient > 0.75). When we compared the PT and WPT groups, we did not find a significant difference in the magnitude of the first (F1) and second (F2) peaks of the VGRF. We also did not find a significant difference in the time to production of these peaks (T1 and T2), and the time to stabilization (TTS) (p < 0. 05). Furthermore, the flight time was similar in the two groups (0.475 ± 0.046 and 0.474 ± 0.056 s, respectively, for PT and WPT). These results suggest that PT does not jeopardize performance during CMJ. Furthermore, it also does not soften the VGRF generated during the landing, indicating that PT may be of limited utility in preventing injuries associated with this type of movement. Key pointsWe investigated whether patellar taping interferes with athletic performance, as has been suggested by previous studies.We also explored the effect of patellar taping on the forces generated during the landing phase of counter movement jumps.Patellar taping had no effect on the flight time during counter movement jumps.Patellar taping also had no effect on the vertical ground reaction force variables measured during the landing phase of counter movement jumps.This information may be relevant to athletes and trainers who are concerned about the effects of patellar taping on performance.