An Extreme Mountain Ultra-Marathon Decreases the Cost of Uphill Walking and Running

Purpose: To examine the effects of the world's most challenging mountain ultramarathon (MUM, 330 km, cumulative elevation gain of +24,000 m) on the energy cost and kinematics of different uphill gaits. Methods: Before (PRE) and immediately after (POST) the competition, 19 male athletes performed three submaximal 5-min treadmill exercise trials in a randomized order: walking at 5 km.h-1, +20%; running at 6 km.h-1, +15%; and running at 8 km.h-1, +10%. During the three trials, energy cost was assessed using an indirect calorimetry system and spatiotemporal gait parameters were acquired with a floor-level high-density photoelectric cells system. Results: The average time of the study participants to complete the MUM was 129 h 43 min 48 s (range: 107 h 29 min 24 s to 144 h 21 min 0 s). Energy costs in walking (-11.5 +/- 5.5%, P < 0.001), as well as in the first (-7.2 +/- 3.1%, P = 0.01) and second (-7.0 +/- 3.9%, P = 0.02) running condition decreased between PRE and POST, with a reduction both in the heart rate (-11.3, -10.0, and -9.3%, respectively) and oxygen uptake only for the walking condition (-6.5%). No consistent and significant changes in the kinematics variables were detected (P-values from 0.10 to 0.96). Conclusion: Though fatigued after completing the MUM, the subjects were still able to maintain their uphill locomotion patterns noted at PRE. The decrease (improvement) in the energy costs was likely due to the prolonged and repetitive walking/running, reflecting a generic improvement in the mechanical efficiency of locomotion after ~130 h of uphill locomotion rather than constraints imposed by the activity on the musculoskeletal structure and function

Neuromuscular, biomechanical, and energetic adjustments following repeated bouts of downhill running

Background: This study used downhill running as a model to investigate the repeated bout effect (RBE) on neuromuscular performance, running biomechanics, and metabolic cost of running. Methods: Ten healthy recreational male runners performed 2 30-min bouts of downhill running (DR1 and DR2) at a -20% slope and 2.8 m/s 3 weeks apart. Neuromuscular fatigue, level running biomechanics during slow and fast running, and running economy parameters were recorded immediately before and after the downhill bouts, and at 24 h, 48 h, 72 h, 96 h, and 168 h thereafter (i.e., follow-up days). Results: An RBE was confirmed by attenuated muscle soreness and serum creatine kinase rise after DR2 compared to DR1. An RBE was also observed in maximum voluntary contraction (MVC) force loss and voluntary activation where DR2 resulted in attenuated MVC force loss and voluntary activation immediately after the run and during follow-up days. The downhill running protocol significantly influenced level running biomechanics; an RBE was observed in which center of mass excursion and, therefore, lower-extremity compliance were greater during followup days after DR1 compared to DR2. The observed changes in level running biomechanics did not influence the energy cost of running. Conclusion: This study demonstrated evidence of adaptation in neural drive as well as biomechanical changes with the RBE after DR. The higher neural drive resulted in attenuated MVC force loss after the second bout. It can be concluded that the RBE after downhill running manifests as changes to global and central fatigue parameters and running biomechanics without substantially altering the energy cost of running

The oxidative-glycolytic balance influenced by sprint duration is key during repeated sprints in hypoxia

Purpose This study investigates the effects of normobaric hypoxia on repeated sprint exercise (RSE) with different balance between oxidative (phosphocreatine and oxidative pathway) and glycolytic contributions. Therefore, performance and psycho-physiological responses were compared during RSE to exhaustion with the same exercise-to-rest ratio (1:2) but different sprint durations (5, 10 or 20s) either in normoxic (RSN) or hypoxic (RSH; FiO2 = 0.13) conditions. Methods On separate visits, 10 active participants completed in random order three cycling RSN (5:10; 10:20 and 20:40) and three similar RSH sessions to exhaustion. Vastus lateralis muscle oxygenation was recorded by near infrared spectroscopy. Blood lactate concentration, limb and breathing discomfort, and ratings of perceived exertion (RPE) were measured. Results Total sprint number was smaller in hypoxia than in normoxia for 5:10 (20.8 ± 8.6 vs 14.7 ± 3.4; p = 0.014) and 10:20 (13.7 ± 6.3 vs 8.8 ± 2.5; p = 0.018) but not 20:40 (5.6 ± 1.9 vs 5.6 ± 2.5). The fatigue index was larger in hypoxia only for 5:10 (-43.5%, p < 0.001). Irrespective of condition, blood lactate concentration increased with the sprint duration with higher values for 20:40 than 5:10 (13.1 ± 2.7 vs 11.5 ± 2.2 mmol.l-1; p = 0.027). Limb and breathing discomfort and RPE did not differ in all RSE. Muscle oxygenation was mainly impacted by sprint duration (i.e., main effect of sprint duration on [HHb] min, [tHb] max, Δ[HHb] and Δ[tHb]) but not by hypoxia. The normoxia-to-hypoxia percentage decrease for total sprint number for 5:10 was correlated with the highest power output over 5 s (R2 = 0.55; p = 0.013) and 10s (R2 = 0.53; p = 0.016). Conclusions Hypoxia impairs repeated sprint ability when the oxidative but not the glycolytic contribution is substantial. The oxidative-glycolytic balance, influenced partly by sprint duration, is key during repeated sprint in hypoxia

Injury and Illness Rates During Ultratrail Running

This study aimed to describe injury/illness rates in ultratrail runners competing in a 65-km race to build a foundation for injury prevention and help race organizers to plan medical provision for these events. Prospectively transcribed medical records were analysed for 77 athletes at the end of the race. Number of injuries/illnesses per 1\u2009000 runners and per 1\u2009000-h run, overall injury/illness rate and 90% confidence intervals and rates for major and minor illnesses, musculoskeletal injuries, and skin disorders were analysed. A total of 132 injuries/illnesses were encountered during the race. The overall injuries/illnesses were 1.9 per runner and 13.1 per 1\u2009000-h run. Medical illnesses were the most prominent medical diagnoses encountered (50.3%), followed by musculoskeletal injuries (32.8%), and skin-related disorders (16.9%). Despite the ultra-long nature of the race, the majority of injuries/illnesses were minor in nature. Medical staff and runners should prepare to treat all types of injuries and illnesses, especially the fatigue arising throughout the course of an ultratrail run and injuries to the lower limbs. Future studies should attempt to systematically identify injury locations and mechanisms in order to better direct injury prevention strategies and plan more accurate medical care

Putative role of circulating human papillomavirus DNA in the development of primary squamous cell carcinoma of the middle rectum: A case report

Here we present the case of a patient affected by rectal squamous cell carcinoma in which we demonstrated the presence of Human Papillomavirus (HPV) by a variety of techniques. Collectively, the virus was detected not only in the tumor but also in some regional lymph nodes and in non-neoplastic mucosa of the upper tract of large bowel. By contrast, it was not identifiable in its common sites of entry, namely oral and ano-genital region. We also found HPV DNA in the plasma-derived exosome. Next, by in vitro studies, we confirmed the capability of HPV DNA-positive exosomes, isolated from the supernatant of a HPV DNA positive cell line (CaSki), to transfer its DNA to human colon cancer and normal cell lines. In the stroma nearby the tumor mass we were able to demonstrate the presence of virus DNA in the stromal compartment, supporting its potential to be transferred from epithelial cells to the stromal ones. Thus, this case report favors the notion that human papillomavirus DNA can be vehiculated by exosomes in the blood of neoplastic patients and that it can be transferred, at least in vitro, to normal and neoplastic cells. Furthermore, we showed the presence of viral DNA and RNA in pluripotent stem cells of non-tumor tissue, suggesting that after viral integration (as demonstrated by p16 and RNA in situ hybridization positivity), stem cells might have been activated into cancer stem cells inducing neoplastic transformation of normal tissue through the inactivation of p53, p21, and Rb. It is conceivable that the virus has elicited its oncogenic effect in this specific site and not elsewhere, despite its wide anatomical distribution in the patient, for a local condition of immune suppression, as demonstrated by the increase of T-regulatory (CD4/CD25/FOXP3 positive) and T-exhausted (CD8/PD-1positive) lymphocytes and the M2 polarization (high CD163/CD68 ratio) of macrophages in the neoplastic microenvironment. It is noteworthy that our findings depicted a static picture of a long-lasting dynamic process that might evolve in the development of tumors in other anatomical sites

Isokinetic strength of foot plantar and dorsal flexors in young male orienteers

Orienteers navigate point to point in unfamiliar and uneven grounds using map and compass to run their races. High levels of fitness and running speed are requested to cover successfully long distances and climbs. Strength in ankle and foot muscles is necessary to overcome natural obstacles in rough terrains (1). Eight male orienteers of junior Italian team (OR; age, 19\ub11.6yr), 8 cross country track and fields experienced runners (TF; 20\ub14.5yr), and 8 sedentary persons (control group CG; 23\ub12.7yr), all with right lower limb dominance volunteered. Ages, weights, heights, and body mass indices between groups did not differ (ANOVA, p>0.05). Each participant performed and an isokinetic dynamometer measured 4 repetitions of right and left foot dorsal and plantar flexions at the angular speeds of 60-120-180deg/sec respectively. Within side, group and angular speed, the ratios of peak torques between plantar and dorsal flexors were also computed. Descriptive statistics were calculated within subject, group, movement, angular speed, and side. For each movement, the effects of group and side, and group 7side interactions on peak torques at different speeds were compared by ANOVA (statistical significance 5%). Within group, dorsal and plantar flexors of right foot were generally stronger than those of contralateral limb, but differences were not significant. Side-related differences were similar in all groups (p>0.05). On average, OR performed larger peak torques in both sides and movements. Differences were significant in foot plantar flexors at 60-120-180deg/sec, and in foot dorsal flexors at 60 and 120deg/sec (p 640.04). In both limbs, the ratios between plantar and dorsal flexors were larger in OR at 120-180deg/sec, and in TF at 60deg/sec (p<0.01). Orienteers build their physical training mostly on overcoming natural obstacles and running on uneven grounds. This approach could stimulate a continuous proprioceptive activity, and favor the reinforcement of ankle and foot muscles. Data could be of interest for coaches to set efficient training plans preventing accidental injuries, and for physical therapists and physicians to quantify the effects of rehabilitation. Investigations should be extended to a larger group of participants and to other muscular districts