Steve H. Faulkner

Reducing muscle temperature drop after warm-up improves sprint cycling performance

PURPOSE This study aimed to determine the effect of passive insulation versus external heating during recovery after a sprint-specific warm-up on thigh muscle temperature and subsequent maximal sprint performance. METHODS On three separate occasions, 11 male cyclists (age = 24.7 ± 4.2 yr, height = 1.82 ± 0.72 m, body mass = 77.9 ± 9.8 kg; mean ± SD) completed a standardized 15-min intermittent warm-up on a cycle ergometer, followed by a 30-min passive recovery period before completing a 30-s maximal sprint test. Muscle temperature was measured in the vastus lateralis at 1, 2, and 3 cm depth before and after the warm-up and immediately before the sprint test. Absolute and relative peak power output was determined and blood lactate concentration was measured immediately after exercise. During the recovery period, participants wore a tracksuit top and (i) standard tracksuit pants (CONT), (ii) insulated athletic pants (INS), or (iii) insulated athletic pants with integrated electric heating elements (HEAT). RESULTS Warm-up increased Tm by approximately 2.5 °C at all depths, with no differences between conditions. During recovery, Tm remained elevated in HEAT compared with INS and CONT at all depths (P < 0.001). Both peak and relative power output were elevated by 9.6% and 9.1%, respectively, in HEAT compared with CONT (both P < 0.05). The increase in blood lactate concentration was greater (P < 0.05) after sprint in HEAT (6.3 ± 1.8 mmol·L(-1)) but not INS (4.0 ± 1.8 mmol·L(-1)) versus CONT (4.1 ± 1.9 mmol·L(-1)). CONCLUSIONS Passive heating of the thighs between warm-up completion and performance execution using pants incorporating electrically heated pads can attenuate the decline in Tm and improve sprint cycling performance.

Pro- and anti-apoptotic roles for IGF-I in TNF-α-induced apoptosis: A MAP kinase mediated mechanism

Objective. The concept of skeletal muscle homeostasis—often viewed as the net balance between two separate processes, namely protein degradation and protein synthesis—are not occurring independently of each other, but are finely co-ordinated by a web of intricate signalling networks. Materials and methods. Using rodent muscle cell lines we have investigated TNF-α/IGF-I interactions, in an attempt to mimic and understand mechanisms underlying the wasting process. Results and conclusion. When myoblast cells are incubated with TNF-α (10 ng ml− 1) maximal damage (∼21% ± 0.7 myoblast death, p < 0.05) was induced. Co-incubation of TNF-α (10 ng ml− 1) with IGF-I resulted in cell survival (∼50% reduction in myoblast death, p < 0.05), however, myotube formation was not evident. In contrast, a novel role of IGF-I has been identified whereby co-incubation of muscle cells with IGF-I (1.5 ng ml− 1) and a non-apoptotic dose of TNF-α (1.25 ng ml− 1; sufficient to block differentiation) unexpectedly were shown not to rescue a block on differentiation but to facilitate significant myoblast death (p < 0.05). Interestingly, pre-administration of PD98059, a MAPK signal-blocking agent followed by co-incubation of 1.25 ng ml− 1 TNF-α and 1.5 ng ml− 1 IGF-I, reduced death to baseline levels (p < 0.05). We show for the first time that IGF-I can be apoptotic in the absence of TNF-α-induced cell death.

Highly manufacturable graphene oxide biosensor for sensitive Interleukin-6 detection

Graphene Oxide (GO) is analogous to graphene with oxygen moieties. It offers several advantages over graphene, such as a tunable band-gap, facile synthesis and no use of metal catalysts. Due to the monolayer configuration of GO, all of its carbon atoms are readily exposed to the atmosphere and are sensitive to surface perturbations, thus making GO very suitable for liquid-gated field effect transistor (FET) type sensing applications. However, there are two main limitations preventing GO usage in practical FET sensors. It displays (1) variable coverage between fabricated chips and (2) high electrical resistance. In this paper, we overcome these two limitations by using a facile atmospheric-pressure ethanol Chemical Vapor Deposition treatment on top of pre-coated GO (ECVDGO) which decreases the electrical resistivity from 1.99 × 106 Ω square−1 to 4.68 × 103 Ω square−1, and resistivity variation from 1.60 × 106 to 7.72 × 102 Ω square−1; whilst enlarging the surface GO coverage up to 100%. We then demonstrate the ability of the post-treated ECVDGO liquid-gated FET transducer to detect Interleukin-6 which is a multi-functional cytokine involved in regulating the immune function and the acute phase response. The sensing window of the fabricated biosensor to Interleukin-6 is within the physiologically-relevant range, from 4.7 to 300 pg ml−1. The LOD of the sensor based on 3σ is 2.9 pA or 1.53 pg ml−1. This study demonstrates the emerging potential of GO with high manufacturability in liquid-gated FET biosensors for sensitive and label-free detection of bio-molecules.

Acute molecular responses to concurrent resistance and high‐intensity interval exercise in untrained skeletal muscle

Concurrent training involving resistance and endurance exercise may augment the benefits of single‐mode training for the purpose of improving health. However, muscle adaptations, associated with resistance exercise, may be blunted by a subsequent bout of endurance exercise, via molecular interference. High‐intensity interval training (HIIT), generating similar adaptations to endurance exercise, may offer an alternative exercise mode to traditional endurance exercise. This study examined the influence of an acute HIIT session on the molecular responses following resistance exercise in untrained skeletal muscle. Ten male participants performed resistance exercise (4 × 8 leg extensions, 70% 1RM, (RE)) or RE followed by HIIT (10 × 1 min at 90% HRmax, (RE+HIIT)). Muscle biopsies were collected from the vastus lateralis before, 2 and 6 h post‐RE to determine intramuscular protein phosphorylation and mRNA responses. Phosphorylation of Akt (Ser473) decreased at 6 h in both trials (P < 0.05). Phosphorylation of mTOR (Ser2448) was higher in RE+HIIT (P < 0.05). All PGC‐1α mRNA variants increased at 2 h in RE+HIIT with PGC‐1α and PGC‐1α‐ex1b remaining elevated at 6 h, whereas RE‐induced increases at 2 and 6 h for PGC‐1α‐ex1b only (P < 0.05). Myostatin expression decreased at 2 and 6 h in both trials (P < 0.05). MuRF‐1 was elevated in RE+HIIT versus RE at 2 and 6 h (P < 0.05). Atrogin‐1 was lower at 2 h, with FOXO3A downregulated at 6 h (P < 0.05). These data do not support the existence of an acute interference effect on protein signaling and mRNA expression, and suggest that HIIT may be an alternative to endurance exercise when performed after resistance exercise in the same training session to optimize adaptations.

Comments on Crosstalk 26: Highintensity interval trainingdoes/does not have a role in riskreduction or treatment ofdisease. Personalised exercise – timeto HIIT the right balance.

This is the peer reviewed version of the following article: PUGH, J.K. and FAULKNER, S.H., 2016. Comments on Crosstalk 26: High intensity interval training does/does not have a role in risk reduction or treatment of disease. Personalised exercise – time to HIIT the right balance. Journal of Physiology, 593(24), pp. 5215–5404., which has been published in final form at http://dx.doi.org/10.1113/JP271041. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. It is a comment on the original article and can be found in supporting information.

The mechanism of graphene oxide as a growth template for complete reduced graphene oxide coverage on an SiO2 substrate

Reduced Graphene Oxide (rGO) has the distinct advantage of an aqueous and industrial-scalable production route. However large deviation in the electrical resistivity of fabricated rGO devices, caused by inhomogeneous coverage of rGO on the substrate, prevents its practical application in electronic devices. This critical problem could be solved by using an ethanol chemical vapour deposition (CVD) treatment on graphene oxide (GO). With the treatment, not only GO is reduced to rGO, but also rGO preferentially grows outwards from the edges of the existing GO template and enlarge in size until rGO completely covers the substrate. The growth sequence is presented and our results indicate that the growth supports the free radical condensate growth mechanism. After the ethanol CVD treatment, the standard deviation in electrical resistivity decreased significantly by 99.95% (1.60 × 106 to 7.72 × 102 Ω per square) in comparison with hydrazine-reduced rGO substrates. As no carbon signatures on the substrate were observed when no template was used, this work indicates that GO could act as a template for subsequent formation of rGO.

A Semi-automated Programme for Tracking Myoblast Migration Following Mechanical Damage: Manipulation by Chemical Inhibitors

Background: Potential roles for undifferentiated skeletal muscle stem cells or satellite cells in muscle hypertrophy and repair have been reported, however, the capacity, the mode and the mechanisms underpinning migration have not been investigated. We hypothesised that damaged skeletal myoblasts would elicit a mesenchymal-like migratory response, which could be precisely tracked and subsequently manipulated. Methods: We therefore established a model of mechanical damage and developed a MATLABTM tool to measure the migratory capacity of myoblasts in a non-subjective manner. Results: Basal migration following damage was highly directional, with total migration distances of 948µm ± 239µm being recorded (average 0-24 hour distances: 491µm ± 113µm and 24-48 hour distances: 460µm ± 218µm). Pharmacological inhibition of MEK or PI3-K using PD98059 (20µM) or LY294002 (5µm), resulted in significant reduction of overall cell migration distances of 38% (p<0.001) and 39.5% (p<0.0004), respectively. Using the semi-automated cell tracking using MATLABTM program we validated that not only was migration distance reduced as a consequence of reduced cell velocity, but critically also as a result of altered directionality of migration. Conclusion: These studies demonstrate that murine myoblasts in culture migrate and provide a good model for studying responsiveness to damage in vitro. They illustrate for the first time the powerful tool that MATLABTM provides in determining that both velocity and directional capacity influence the migratory potential of cellular movement with obvious implications for homing and for metastases.

Conductive and evaporative precooling lowers mean skin temperature and improves time trial performance in the heat

Self‐paced endurance performance is compromised by moderate‐to‐high ambient temperatures that are evident in many competitive settings. It has become common place to implement precooling prior to competition in an attempt to alleviate perceived thermal load and performance decline. The present study aimed to investigate precooling incorporating different cooling avenues via either evaporative cooling alone or in combination with conductive cooling on cycling time trial performance. Ten trained male cyclists completed a time trial on three occasions in hot (35 °C) ambient conditions with the cooling garment prepared by (a) immersion in water (COOL, evaporative); (b) immersion in water and frozen (COLD, evaporative and conductive); or (c) no precooling (CONT). COLD improved time trial performance by 5.8% and 2.6% vs CONT and COOL, respectively (both P < 0.05). Power output was 4.5% higher for COLD vs CONT (P < 0.05). Mean skin temperature was lower at the onset of the time trial following COLD compared with COOL and CONT (both P < 0.05) and lasted for the first 20% of the time trial. Thermal sensation was perceived cooler following COOL and COLD. The combination of evaporative and conductive cooling (COLD) had the greatest benefit to performance, which is suggested to be driven by reduced skin temperature following cooling.

Tapering strategies in elite British endurance runners

Abstract The aim of the study was to explore pre-competition training practices of elite endurance runners. Training details from elite British middle distance (MD; 800 m and 1500 m), long distance (LD; 3000 m steeplechase to 10,000 m) and marathon (MAR) runners were collected by survey for 7 days in a regular training (RT) phase and throughout a pre-competition taper. Taper duration was [median (interquartile range)] 6 (3) days in MD, 6 (1) days in LD and 14 (8) days in MAR runners. Continuous running volume was reduced to 70 (16)%, 71 (24)% and 53 (12)% of regular levels in MD, LD and MAR runners, respectively (P < 0.05). Interval running volume was reduced compared to regular training (MD; 53 (45)%, LD; 67 (23)%, MAR; 64 (34)%, P < 0.05). During tapering, the peak interval training intensity was above race speed in LD and MAR runners (112 (27)% and 114 (3)%, respectively, P < 0.05), but not different in MD (100 (2)%). Higher weekly continuous running volume and frequency in RT were associated with greater corresponding reductions during the taper (R = −0.70 and R = −0.63, respectively, both P < 0.05). Running intensity during RT was positively associated with taper running intensity (continuous intensity; R = 0.97 and interval intensity; R = 0.81, both P < 0.05). Algorithms were generated to predict and potentially prescribe taper content based on the RT of elite runners. In conclusion, training undertaken prior to the taper in elite endurance runners is predictive of the tapering strategy implemented before competition.

Interleukin-6 in combination with the interleukin-6 receptor stimulates glucose uptake in resting human skeletal muscle independently of insulin action

To examine if the physiological concentrations of both interleukin‐6 (IL‐6), in combination with IL‐6 receptor (IL‐6R), are able to stimulate glucose uptake in human skeletal muscle and to identify the associated signalling pathways.