The aim of this study was to investigate the effects of 12 weeks of high-intensity training with astaxanthin supplementation on adipokine levels, insulin resistance and lipid profiles in males with obesity. Sixty-eight males with obesity were randomly stratified into four groups of seventeen subjects each: control group (CG), supplement group (SG), training group (TG), and training plus supplement group (TSG). Participants underwent 12 weeks of treatment with astaxanthin or placebo (20 mg/d capsule daily). The training protocol consisted of 36 sessions of high-intensity functional training (HIFT), 60 min/sessions, and three sessions/week. Metabolic profiles, body composition, anthropometrical measurements, cardio-respiratory indices and adipokine [Cq1/TNF-related protein 9 and 2 (CTRP9 and CTRP2) levels, and growth differentiation factors 8 and 15 (GDF8 and GDF15)] were measured. There were significant differences for all indicators between the groups (p < 0.05). Post-hoc analysis indicated that the levels of CTRP9, CTRP2, and GDF8 were different from CG (p < 0.05), although levels of GDF15 were similar to CG (p > 0.05). Levels of GDF8 were similar in the SG and TG groups (p > 0.05), with reductions of GDF15 levels in both training groups (p < 0.05). A total of 12 weeks of astaxanthin supplementation and exercise training decreased adipokines levels, body composition (weight, %fat), anthropometrical factors (BMI), and improved lipid and metabolic profiles. These benefits were greater for men with obesity in the TSG group.

Stretching the antagonist muscle to enhance agonist performance has gained considerable attention. However, most studies have focused on one stretching duration. Hence, the aim of this study was to compare varying durations (40-, 80-, and 120-seconds) of antagonist (dorsiflexors) static stretching (SS) on agonist (plantar flexors: PF) muscle performance. In this randomized crossover study, 16 participants (six females) underwent four sessions (40-, 80-, 120-s dorsiflexors SS and control), with pre- and post-intervention measurements of slow (600/s) and fast (2400/s) PF isokinetic, isometric peak torque, total work, stiff leg drop jump (SDJ) performance (height, reactive strength index (RSI) and peak power), and tibialis anterior and soleus electromyography (EMG). Dorsiflexors SS protocol involved 1x40-s (40-s), 2x40-s (80-s), and 3x40-s (120-s). There were no significant pre- to post-intervention changes in any parameter. A main effect for time demonstrated an overall decrease in fast (p < 0.0001, 5.9%, d = 0.24) and slow (p = 0.05, 6.6%, d = 0.24) isokinetic peak torque, total work (p = 0.02, 5.1%, d = 0.20) and all SDJ measures (SDJ height: p = 0.02, 2.7%, d = 0.15, RSI: p < 0.0001, 5.9%, d = 0.23, peak power: p = 0.002, 4.4%, d = 0.22). Soleus EMG decreased from pre- to post-SS after 120-s in both isometric (p = 0.002, 13.6%, d = 0.73) and slow isokinetic (p = 0.002, 12.3%, d = 0.91) peak torque as well as 80-s with slow isokinetic peak torque (p = 0.02, 6.6%, d = 0.75). In summary, different durations of dorsiflexors SS (40-s, 80-s, 120-s) did not significantly influence PF performance. However, deficits associated with a main effect for time suggested possible testing effects as detected with the control condition.

Here we show that training and sex alter central and peripheral neuromuscular output measures due to morphological and physiological differences and adaptations. These differences should be taken into consideration when designing studies to determine mechanisms underlying changes in neuromuscular output, especially when considering corticospinal excitability and whether or not it is normalized between and within participants.

Purpose: This study investigated whether an acute bout of submaximal unilateral arm cycling elicits sustained changes in corticospinal excitability (CSE) and short-interval intracortical inhibition (SICI) in the homologous muscles of the non-exercised, resting limb. A secondary aim was to determine whether prior exercise induces a preconditioning effect on subsequent motor output. Methods: Transcranial magnetic stimulation was used to assess motor evoked potential (MEP) amplitude (single-pulse) and SICI (paired-pulse) in the resting non-dominant flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles of healthy participants. Measures were obtained at rest, during a 10 min bout of unilateral arm cycling (30 W, 60 rpm), and throughout a 20 min recovery period. To assess potential preconditioning effects, measurements were repeated during a second 2 min cycling bout following a 20 min recovery. Rest and exercise conditions were analyzed separately due to differences in stimulation intensity (RMT vs. AMT). Results: Unilateral arm cycling did not produce sustained changes in CSE or SICI in the resting limb when both arms were at rest. Furthermore, unilateral arm cycling followed by a 20 min recovery period did not result in a preconditioning effect, as CSE in the resting limb was not enhanced during a subsequent unilateral arm cycling bout. Conclusions: Submaximal unilateral arm cycling induces a transient, state-dependent increase in CSE to the non-exercised limb without altering SICI. The absence of SICI modulation suggests that this facilitation is not mediated by GABA_A-dependent intracortical mechanisms, and may instead reflect modulation arising from spinal and interlimb locomotor circuitry. The lack of sustained post-exercise effects indicates that low-intensity arm cycling does not induce a plasticity-permissive cortical state, highlighting a distinction between transient, movement-dependent facilitation and longer-lasting exercise-induced neuroplasticity.