Pre‐exercise whole‐body cooling decreases blood volume and oxygenated hemoglobin content in skeletal muscle during submaximal exercise (1106.7)

The effects of skin and core tissue cooling on oxygenation of the vastus lateralis muscle during walking and running

Skin and core tissue cooling modulates skeletal muscle oxygenation at rest. Whether tissue cooling also influences the skeletal muscle deoxygenation response during exercise is unclear. We evaluated the effects of skin and core tissue cooling on skeletal muscle blood volume and deoxygenation during sustained walking and running. Eleven male participants walked or ran six times on a treadmill for 60 min in ambient temperatures of 22°C (Neutral), 0°C for skin cooling (Cold 1), and at 0°C following a core and skin cooling protocol (Cold 2). Difference between oxy/deoxygenated haemoglobin ([diffHb]: deoxygenation index) and total haemoglobin content ([tHb]: total blood volume) in the vastus lat…

Fuel selection during short-term submaximal treadmill exercise in the cold is not affected by pre-exercise low-intensity shivering.

Exercise and shivering rely on different metabolic pathways and consequently, fuel selection. The present study examined the effects of a pre-exercise low-intensity shivering protocol on fuel selection during submaximal exercise in a cold environment. Nine male subjects exercised 4 times for 60 min at 50% (LOW) or 70% (MOD) of their peak oxygen consumption on a motorized treadmill in a climatic chamber set at 0 °C with (SHIV) and without (CON) a pre-exercise cooling protocol, inducing low-intensity shivering. Thermal, cardiorespiratory and metabolic responses were measured every 15 min whereas blood samples were collected every 30 min to assess serum nonesterified fatty acids (NEFA), glyce…

Microdialysis-Assessed Exercised Muscle Reveals Localized and Differential IGFBP Responses to Unilateral Stretch Shortening Cycle Exercise

Microdialysis allows for a preview into local muscle metabolism and can provide physiological insight that blood measurements cannot. Purpose: To examine the potential differential IGF-I system regulation in interstitial fluid during unilateral stretch shortening cycle exercise. Methods: 10 men (26 ± 7 year) performed unilateral jumping [stretch shortening cycle (SSC) exercise at 50% of optimal jump height] until volitional fatigue on a sled apparatus. Biological sampling took place using a catheter inserted into an antecubital vein (serum), and 100 kDa microdialysis probes inserted into the thigh muscle of each exercise/control leg (dialysate). Serum was drawn before (Pre; −3 h) and after …

Basal Endogenous Steroid Hormones, Sex Hormone-Binding Globulin, Physical Fitness, and Health Risk Factors in Young Adult Men.

Purpose: Few large-scale population-based studies have adequately examined the relationships between steroid hormones, health status and physical fitness. The purpose of the study was to describe the relationship of serum basal endogenous steroid hormones (testosterone, TES; empirical free testosterone, EFT; cortisol, COR) and sex hormone-binding globulin (SHBG) to body composition, cardiovascular risk factors, and physical fitness in young healthy men. Methods: Male reservists (25 ± 4 years, N = 846) participated in the study. Basal TES, EFT, COR, and SHBG were measured in morning fasted blood. Stepwise regression analyses were used to examine associations between individual hormones to fo…

Active recovery shows favorable IGF-I and IGF binding protein responses following heavy resistance exercise compared to passive recovery

IGF-I and IGFBPs have important physiological modulatory effects and this study sought to examine the influence of active vs. passive recovery following a heavy resistance exercise on IGF-I and IGF binding protein (IGFBP) recovery responses. It was hypothesized that increased IGF-I and decreased inhibitory IGFBPs during active recovery may be reflective of cascades promoting physiological recovery. 18 untrained men ((AR n = 7, PR n = 11), age: 26 ± 4 years, height: 174 ± 8 cm, body mass: 75 ± 13 kg) performed either a protocol-specific 10 × 10 × 30% 1RM active (AR) or passive recovery (PR) session following a heavy resistance exercise session performed on a leg press device (10 × 10 1RM). M…

The Effects of Cold Exposure on Leukocytes, Hormones and Cytokines during Acute Exercise in Humans

The purpose of the study was to examine the effects of exercise on total leukocyte count and subsets, as well as hormone and cytokine responses in a thermoneutral and cold environment, with and without an individualized pre-cooling protocol inducing low-intensity shivering. Nine healthy young men participated in six experimental trials wearing shorts and t-shirts. Participants exercised for 60 min on a treadmill at low (LOW: 50% of peak VO2) and moderate (MOD: 70% VO2peak) exercise intensities in a climatic chamber set at 22°C (NT), and in 0°C (COLD) with and without a pre-exercise low-intensity shivering protocol (SHIV). Core and skin temperature, heart rate and oxygen consumption were col…

Valmentajat avainasemassa nuorten polvivammojen ehkäisyssä

Eturistisidevammojen ennaltaehkäisyyn tähtäävä hermo-lihasharjoitusohjelma voidaan toteuttaa osana alkulämmittelyä ennen harjoittelua. nonPeerReviewed

Human skeletal muscle type 1 fibre distribution and response of stress-sensing proteins along the titin molecule after submaximal exhaustive exercise.

Early responses of stress-sensing proteins, muscle LIM protein (MLP), ankyrin repeat proteins (Ankrd1/CARP and Ankrd2/Arpp) and muscle-specific RING finger proteins (MuRF1 and MuRF2), along the titin molecule were investigated in the present experiment after submaximal exhaustive exercise. Ten healthy men performed continuous drop jumping unilaterally on a sledge apparatus with a submaximal height until complete exhaustion. Five stress-sensing proteins were analysed by mRNA measurements from biopsies obtained immediately and 3 h after the exercise from exercised vastus lateralis muscle while control biopsies were obtained from non-exercised legs before the exercise. Decreased maximal jump h…