Effect of cycling specialization on effort and physiological responses to uphill and flat cycling at similar intensity

[EN] Power output is considered one of the best tools to control external loads in cycling, but the relationship between a target power output and the physiological responses may suffer from the effects of road gradient, which is also affected by cyclist specialization. The objective was to determine the effects of cyclist specialization on effort perception and physiological response (heart rate and lactate concentration) while sustaining efforts at similar power output but riding on two different road gradients. Nineteen male competitive road cyclists performed two randomized trials of 10 min at 0% (velodrome) and 10 min at 6% road gradient (field uphill), at an intensity of 10% ± 3% below the individual’s functional threshold power. Cadence was kept between 75 and 80 rpm in both trials and posture remained unchanged during the tests. Heart rate, speed, cadence, power output, blood lactate, and rate of perceived effort were measured for each trial. K-means cluster analyses differentiate uphill (n = 10) and flat specialists (n = 9) according to lactate responses. Flat specialists presented lower heart rate (p < 0.001 and ES = 0.2), perceived exertion (p < 0.01 and ES = 0.7), and blood lactate concentration (p < 0.001 and ES = 0.7) riding on the flat than uphill. Uphill specialists presented lower perceived exertion (p < 0.01 and ES = 0.8) and blood lactate concentration (p < 0.01 and ES = 0.5) riding uphill than on the flat. In conclusion, the combination of cyclist specialization and road gradient affects physiological and effort perception parameters in response to a similar power output demand. These factors deserve attention in training schedules and monitoring performance using power output data.S

Effect of fatigue strength exercise on anterior thigh skin temperature rewarming after cold stress test

Although dynamic thermography skin temperature assessment has been used in medical field, scientific evidence in sports is scarce. The aim of the study was to assess changes in anterior thigh skin temperature in response to a cold stress test after a strength exercise fatiguing protocol. Ten physically active adults performed a familiarization session and two strength exercise sessions, one with dominant and the other with non-dominant lower limb. Participants performed bouts of 10 concentric and eccentric contractions of leg extensions in an isokinetic device until reaching around 30% of force loss. Infrared thermographic images were taken at baseline conditions and after the fatigue level from both thighs after being cooled using a cryotherapy system. ROIs included vastus medialis, rectus femoris, adductor and vastus lateralis. Skin temperature rewarming was assessed during 180s after the cooling process obtaining the coefficients of the following equation: ΔSkin temperature = β0 + β1 * ln(T), being β0 and β1 the constant and slope coefficients, respectively, T the time elapsed following the cold stress in seconds, and ΔSkin temperature the difference between the skin temperature at T respect and the pre-cooling moment. Lower β0 and higher β1 were found for vastus lateralis and rectus femoris in the intervention lower limb compared with baseline conditions (p  0.6). Adductor only showed differences in β0 (p = 0.01 and ES = 0.92). The regressions models obtained showed that β0 and β1 had a direct relationship with age and muscle mass, but an inverse relationship with the number of series performed until 30% of fatigue (R2 = 0.8). In conclusion, fatigue strength exercise results in a lower skin temperature and a faster thermal increase after a cold stress test

Effects of wearing a full body compression garment during recovery from an ultra-trail race

In sport disciplines with high levels of muscle damage such as an ultra-trail competition, full body compression garments (FBCG) may have an ergogenic effect during the recovery process. The aim of the study was to assess the influence of FBCG worn for 24 h immediately after a 107-km ultra-trail on delayed onset muscle soreness (DOMS), muscle damage, inflammatory and renal response. Thirty-two athletes (19 males and 13 females; VO2peak: 54.1 ± 5.2 ml O2/kg/min) participated in the study. The following blood markers were analysed before, immediately after, at 24 and 48 h post-race: lactate dehydrogenase, creatine kinase, C-reactive protein and creatinine. The glomerular filtration rate was also calculated. Delayed onset muscle soreness was evaluated before, immediately after and at 24 h post-race. On arrival at the finishing line, athletes were randomised into one of two recovery groups (FBCG and control group). The results showed that wearing FBCG did not influence the evolution of any of the blood markers up to 48 h after the race (p > .05). However, FBCG group presented a lower increase in posterior leg DOMS (11.0 ± 46.2% vs 112.3 ± 170.4%, p = .03, d = 0.8). Therefore, although FBCG is not useful for reducing muscle damage and inflammatory response after an ultra-trail race, its use may still be recommended as a recovery method to reduce muscle soreness

Relationship between foot eversion and thermographic foot skin temperature after running

[EN] The main instruments to assess foot eversion have some limitations (especially for field applications), and therefore it is necessary to explore new methods. The objective was to determine the relationship between foot eversion and skin temperature asymmetry of the foot sole (difference between medial and lateral side), using infrared thermography. Twenty-two runners performed a running test lasting 30 min. Skin temperature of the feet soles was measured by infrared thermography before and after running. Foot eversion during running was measured by kinematic analysis. Immediately after running, weak negative correlations were observed between thermal symmetry of the rearfoot and eversion at contact time, and between thermal symmetry of the entire plantar surface of the foot and maximum eversion during stance phase (r = −0.3 and p = 0.04 in both cases). Regarding temperature variations, weak correlations were also observed (r = 0.4 and p < 0.05). The weak correlations observed in this study suggest that skin temperature is not related to foot eversion. However, these results open interesting future lines of researchSIDirección General de Investigación Científica y 397 Técnica (DGICT) (DEP2013-48420-P); Ministerio de 398 Educación, Cultura y Deporte (MECD) (Doctoral 399 Fellowship (FPU))

Effect of fatigue strength exercise on anterior thigh skin temperature rewarming after cold stress test

Although dynamic thermography skin temperature assessment has been used in medical field, scientific evidence in sports is scarce. The aim of the study was to assess changes in anterior thigh skin temperature in response to a cold stress test after a strength exercise fatiguing protocol. Ten physically active adults performed a familiarization session and two strength exercise sessions, one with dominant and the other with non-dominant lower limb. Participants performed bouts of 10 concentric and eccentric contractions of leg extensions in an isokinetic device until reaching around 30% of force loss. Infrared thermographic images were taken at baseline conditions and after the fatigue level from both thighs after being cooled using a cryotherapy system. ROIs included vastus medialis, rectus femoris, adductor and vastus lateralis. Skin temperature rewarming was assessed during 180s after the cooling process obtaining the coefficients of the following equation: ΔSkin temperature = β0 + β1 * ln(T), being β0 and β1 the constant and slope coefficients, respectively, T the time elapsed following the cold stress in seconds, and ΔSkin temperature the difference between the skin temperature at T respect and the pre-cooling moment. Lower β0 and higher β1 were found for vastus lateralis and rectus femoris in the intervention lower limb compared with baseline conditions (p 0.6). Adductor only showed differences in β0 (p = 0.01 and ES = 0.92). The regressions models obtained showed that β0 and β1 had a direct relationship with age and muscle mass, but an inverse relationship with the number of series performed until 30% of fatigue (R² = 0.8). In conclusion, fatigue strength exercise results in a lower skin temperature and a faster thermal increase after a cold stress test.S

Effects of different hydration supports on stride kinematics, comfort, and impact accelerations during running

Background: Different supports for hydration can influence total body mass and affect running biomechanics. Research question: Do different hydration supports affect the perceived exertion and comfort, stride kinematics, and impact accelerations during running?. Methods: This was a crossover study design. Thirteen trail runners completed a treadmill running test divided into four different durations and randomized hydration supports conditions, lasting 8 min each at moderate intensity: A) waist bag (0.84 kg); B) medium load backpack (0.84 kg); C) full load backpack (3.40 kg); and D) a control condition without water support. Impact accelerations were measured for 30 s in 4, 6, and 8 min. The rate of perceived exertion and heart rate were registered on minutes 4 and 8. At the last minute of each condition, comfort perception was registered. Results and significance: No condition affected the stride kinematics. Full load backpack condition reduced head acceleration peak (−0.21 g; p = 0.04; ES=0.4) and head acceleration magnitude (−0.23 g; p = 0.03; ES=0.4), and increased shock attenuation (3.08 g; p = 0.04; ES=0.3). It also elicited higher perceived exertion (p 0.8) being considered heavier (p 1.1). The waist bag condition was more comfortable in terms of noise (p = 0.006; ES=1.3) and humidity/heat (p = 0.001; ES=0.8). The waist bag was the most comfortable support. On the other hand, the full backpack elicited lower comfort and was the only generating compensatory adjustments. These results may help to improve design of full load backpack aiming at comfort for runners

Consistency of pacing profile according to performance level in three different editions of the Chicago, London, and Tokyo marathons

[EN] Running pacing has become a focus of interest over recent years due to its relationship with performance, however, it is still unknown the consistency of each race in different editions. The aim of this study is to analyze the consistency of pacing profile in three consecutive editions of three marathon races. A database of 282,808 runners, compiled from three different races (Chicago, London, and Tokyo Marathon) and three editions (2017, 2018, and 2019) was analyzed. Participants were categorized according to their time performance in the marathon, every 30 min from 2:30 h to sub-6 h. The relative speed of each section for each runner was calculated as a percentage of the average speed for the entire race. The intraclass correlation coefficients (ICC) of relative speed at the different pacing section, taking into account the runner time categories, was excellent over the three marathon editions (ICC > 0.93). The artificial intelligence model showed an accuracy of 86.8% to classify the runners' data in three marathons, suggesting a consistency between editions with identifiable differences between races. In conclusion, although some differences have been observed between editions in certain sections and marathon runner categories, excellent consistency of the pacing profile was observed. The study of pacing profile in a specific marathon can, therefore, be helpful for runners, coaches and marathon organizers for planning the race and improving its organization.Oficial-Casado, F.; Uriel-Molto, J.; Jimenez-Perez, I.; Fagundes Goethel, M.; Pérez-Soriano, P.; Priego-Quesada, JI. (2022). Consistency of pacing profile according to performance level in three different editions of the Chicago, London, and Tokyo marathons. Scientific Reports. 12(1):1-9. https://doi.org/10.1038/s41598-022-14868-61912

Impact accelerations during a prolonged run using a microwavable self-customised foot orthosis

[EN] The use of custom-made foot orthoses has been associated with numerous benefits, such as decreased impact accelerations. However, it is not known whether this effect could be due to better customisation. The present study analysed the effects of the first generation of a microwavable prefabricated self-customised foot orthosis vs. a prefabricated standard one on impact accelerations throughout a prolonged run. Thirty runners performed two tests of 30-min running on a treadmill, each one with an orthosis condition. Impact acceleration variables of tibia and head were recorded every 5 min. Microwavable self-customised foot orthosis increased the following variables in the first instants compared to the prefabricated standard one: tibial peak (min1: 6.5 (1.8) vs. 6.0 (1.7) g, P = .009, min5: 6.6 (1.7) vs. 6.2 (1.7) g, P = .035), tibial magnitude (min1: 8.3 (2.6) vs. 7.7 (2.4) g, P = .030, min5: 8.5 (2.6) vs. 7.9 (2.5) g, P = .026) and shock attenuation (min1: 61.4 (16.8) vs. 56.3 (16.3)%, P = .014, min5: 62.0 (15.5) vs. 57.2 (15.3)%, P = .040), and tibial rate throughout the entire run (504.3 (229.7) vs. 422.7 (212.9) g/s, P = .006). However, it was more stable throughout 30-min running (P < .05). These results show that the shape customisation entailed by the thermoformable material does not provide impact acceleration improvements.This work was supported by the Centre for Industrial Technological Development (CDTI) [Project SPORT@FUTURE (IDI 20141290-IDI 20141296)], and the work of IJP was supported by the Ministry of Science, Innovation and Universities of the Spanish Government [grant number FPU 14/05626].Jiménez-Pérez, I.; Priego-Quesada, JI.; Camacho-García, A.; Cibrian Ortiz De Anda, RM.; Pérez-Soriano, P. (2021). Impact accelerations during a prolonged run using a microwavable self-customised foot orthosis. Sports Biomechanics. 1-15. https://doi.org/10.1080/14763141.2021.190255311

Quantitative Analysis of Real-Time Infrared Thermography for the Assessment of Lumbar Sympathetic Blocks: A Preliminary Study

[EN] Lumbar sympathetic blocks (LSBs) are commonly performed to treat pain ailments in the lower limbs. LSBs involve injecting local anesthetic around the nerves. The injection is guided by fluoroscopy which is sometimes considered to be insufficiently accurate. The main aim was to analyze the plantar foot skin temperature data acquired while performing LSBs in patients with complex regional pain syndrome (CRPS) affecting the lower limbs. Forty-four LSBs for treating lower limb CRPS in 13 patients were assessed. Pain medicine physicians visualized the infrared thermography (IRT) video in real time and classified the performance depending on the observed thermal changes within the first 4 min. Thirty-two percent of the cases did not register temperature variations after lidocaine was injected, requiring the needle to be relocated. Differences between moments are indicated using the 95% confidence intervals of the differences (CI 95%), the Cohen effect size (ES) and the significance (p value). In successful cases, after injecting lidocaine, increases at minute 7 for the mean (CI 95% (1.4, 2.1 °C), p < 0.001 and ES = 0.5), at minute 5 for maximum temperature (CI 95% (2.3, 3.3 °C), p < 0.001 and ES = 0.6) and at minute 6 for SD (CI 95% (0.2, 0.3 °C), p < 0.001 and ES = 0.5) were observed. The results of our preliminary study showed that the measurement of skin temperature in real time by infrared thermography is valuable for assessing the success of lumbar sympathetic blocks.Cañada-Soriano, M.; Priego-Quesada, JI.; Bovaira, M.; García-Vitoria, C.; Salvador Palmer, R.; Ortiz De Anda, RC.; Moratal, D. (2021). Quantitative Analysis of Real-Time Infrared Thermography for the Assessment of Lumbar Sympathetic Blocks: A Preliminary Study. Sensors. 21(11):1-17. https://doi.org/10.3390/s21113573S117211

Footwear outsole temperature may be more related to plantar pressure during a prolonged run than foot temperature

Objective: The temperature of the sole of the foot has been suggested as an alternative to the measurement of plantar pressure during running despite the scarce evidence about their relationship. The temperature of the footwear outsole could also be representative of plantar pressure distribution due to its less multifactorial dependence. The aim of the study was to determine if plantar pressure during a prolonged run could be related to plantar temperature, either of the sole of the foot or the footwear outsole. Approach: Thirty recreational runners (15 males and 15 females) performed a 30-minute running test on a treadmill. Thermographic images of the sole of the foot and the footwear outsole were taken before and immediately after the test, and dynamic plantar pressure was measured at the end of the test. Pearson correlations and stepwise multiple linear regressions were performed. Main results: Plantar pressure percentage was related to a moderate correlation with plantar temperature percentage in forefoot and rearfoot (P<0.05), showing a greater relationship with the footwear outsole than with the sole of the foot (r=0.52–0.73 vs r=0.40–0.61, respectively). Moreover, moderate correlations were also observed between footwear outsole and sole of the foot temperature variables, especially in rearfoot. Significance: Footwear outsole temperature may be better related to plantar pressure distribution than sole of the foot temperature, in the forefoot and rearfoot. The midfoot is the most sensitive and variable region to analyze, as it does not seem to have any relationship with plantar pressure