scholarly journals Maximal strength training-induced increase in efferent neural drive is not reflected in relative protein expression of SERCA

2021 ◽  
Author(s):  
Tiril Tøien ◽  
Håvard Haglo ◽  
Stian Kwak Nyberg ◽  
Shalini Vasudev Rao ◽  
Astrid Kamilla Stunes ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Expression ◽  
Strength Training ◽  
High Intensity ◽  
Force Production ◽  
H Reflex ◽  
Maximal Strength ◽  
Neural Drive ◽  
M Wave ◽  
Neural Adaptations

Abstract Introduction Maximal strength training (MST), performed with heavy loads (~ 90% of one repetition maximum; 1RM) and few repetitions, yields large improvements in efferent neural drive, skeletal muscle force production, and skeletal muscle efficiency. However, it is elusive whether neural adaptations following such high intensity strength training may be accompanied by alterations in energy-demanding muscular factors. Methods Sixteen healthy young males (24 ± 4 years) were randomized to MST 3 times per week for 8 weeks (n = 8), or a control group (CG; n = 8). Measurements included 1RM and rate of force development (RFD), and evoked potentials recordings (V-wave and H-reflex normalized to M-wave (M) in the soleus muscle) applied to assess efferent neural drive to maximally contracting skeletal muscle. Biopsies were obtained from vastus lateralis and analyzed by western blots and real-time PCR to investigate the relative protein expression and mRNA expression of Sarcoplasmic Reticulum Ca2+ ATPase (SERCA) 1 and SERCA2. Results Significant improvements in 1RM (17 ± 9%; p < 0.001) and early (0–100 ms), late (0–200 ms) and maximal RFD (31–53%; p < 0.01) were observed after MST, accompanied by increased maximal Vmax/Msup-ratio (9 ± 14%; p = 0.046), with no change in H-reflex to M-wave ratio. No changes were observed in the CG. No pre- to post-training differences were found in mRNA or protein expressions of SERCA1 and SERCA2 in either group. Conclusion MST increased efferent neural drive to maximally contracting skeletal muscle, causing improved force production. No change was observed in SERCA expression, indicating that responses to high intensity strength training may predominantly be governed by neural adaptations.

scholarly journals Heat acclimation has a protective effect on the central but not peripheral nervous system

2017 ◽  
Vol 123 (4) ◽  
pp. 816-824 ◽  
Author(s):  
Sebastien Racinais ◽  
Mathew G. Wilson ◽  
Nadia Gaoua ◽  
Julien D. Périard
Keyword(s):  
Working Memory ◽  
Executive Function ◽  
Conduction Velocity ◽  
Heat Acclimation ◽  
H Reflex ◽  
Voluntary Activation ◽  
Neural Drive ◽  
M Wave ◽  
Neural Adaptations ◽  
C 50

This study aimed to clarify the pathway mediating hyperthermia-induced alterations in neural drive transmission and determine if heat acclimation protects voluntary muscle activation and cognitive function in hyperthermic humans. Electrically evoked potentials (H reflex and M wave), executive function (special planning and working memory), and maximal voluntary isometric contractions (120 s) were assessed in 14 participants in control conditions [CON, 24°C, 40% relative humidity (RH)] and in a hyperthermic state (HYP, 44–50°C, 50% RH) on consecutive days in a counterbalanced order. Thereafter, participants were passively heat acclimated for 11 days (1 h per day, 48–50°C, 50% RH) before repeating the initial assessments. Heat acclimation decreased rectal temperature in CON (−0.2°C, P < 0.05), but participants were maintained at ~39°C in HYP. Heat acclimation increased the time required to reach 39°C (+9 min), along with sweat rate (+0.7 l/h), and serum extracellular expression of heat shock protein 72 (eHSP72; +20%) in HYP ( P < 0.05). M-wave and H-reflex amplitudes were lower in HYP than CON ( P < 0.05) and were not protected by heat acclimation. Nerve conduction velocity was faster in HYP than CON ( P < 0.05) without being influenced by heat acclimation. These results suggest that peripheral neural drive transmission in the hyperthermic state is primarily affected by axonal conduction velocity rather than synaptic failure. Executive function, voluntary activation, and the ability to sustain torque were impaired in HYP ( P < 0.05). However, despite no perceptual changes ( P > 0.05), heat acclimation restored executive function, while protecting the ability to sustain voluntary activation and torque production during a prolonged contraction in hyperthermia ( P < 0.05). Ultimately, heat acclimation induces beneficial central but not peripheral neural adaptations. NEW & NOTEWORTHY Heat acclimation restores planning accuracy and working memory in hyperthermic humans, together with the supraspinal capacity to sustain motor drive during a sustained maximal voluntary contraction. Electrically evoked potential data (M wave, H reflex) indicate that heat acclimation does not protect against hyperthermia-induced impairments in peripheral neural drive transmission. Heat acclimation induces beneficial central but not peripheral neural adaptations.

scholarly journals Maximal strength training: the impact of eccentric overload

2018 ◽  
Vol 120 (6) ◽  
pp. 2868-2876 ◽  
Author(s):  
Tiril Tøien ◽  
Håvard Pedersen Haglo ◽  
Runar Unhjem ◽  
Jan Hoff ◽  
Eivind Wang
Keyword(s):  
Strength Training ◽  
Motor Unit ◽  
High Intensity ◽  
Firing Frequency ◽  
Motor Unit Recruitment ◽  
Maximal Strength ◽  
Neural Drive ◽  
Generating Capacity ◽  
The Impact ◽  
Eccentric Overload

The search for the most potent strength training intervention is continuous. Maximal strength training (MST) yields large improvements in force-generating capacity (FGC), largely attributed to efferent neural drive enhancement. However, it remains elusive whether eccentric overload, before the concentric phase, may augment training-induced neuromuscular adaptations. A total of 53 23 ± 3 (SD)-yr-old untrained males were randomized to either a nontraining control group (CG) or one of two training groups performing leg press strength training with linear progression, three times per week for 8 wk. The first training group carried out MST with four sets of four repetitions at ~90% one-repetition maximum (1RM) in both action phases. The second group performed MST with an augmented eccentric load of 150% 1RM (eMST). Measurements were taken of 1RM and rate of force development (RFD), countermovement jump (CMJ) performance, and evoked potentials recordings [V-wave (V) and H-reflex (H) normalized to M-wave (M) in musculus soleus]. 1RM increased from 133 ± 16 to 157 ± 23 kg and 123 ± 18 to 149 ± 22 kg and CMJ by 2.3 ± 3.6 and 2.2 ± 3.7cm for MST and eMST, respectively (all P < 0.05). Early, late, and maximal RFD increased in both groups [634–1,501 N/s (MST); 644–2,111 N/s (eMST); P < 0.05]. These functional improvements were accompanied by increased V/M-ratio (MST: 0.34 ± 0.11 to 0.42 ± 14; eMST: .36 ± 0.14 to 0.43 ± 13; P < 0.05). Resting H/M-ratio remained unchanged. Training-induced improvements did not differ. All increases, except for CMJ, were different from the CG. MST is an enterprise for large gains in FGC and functional performance. Eccentric overload did not induce additional improvements, suggesting firing frequency and motor unit recruitment during MST may be maximal. NEW & NOTEWORTHY This is the first study to apply evoked potential recordings to investigate effects on efferent neural drive following high-intensity strength training with and without eccentric overload in a functionally relevant lower extremity exercise. We document that eccentric overload does not augment improvements in efferent neural drive or muscle force-generating capacity, suggesting that high-intensity concentric loads may maximally tax firing frequency and motor unit recruitment.

Effects of high-intensity intermittent swimming on PGC-1alpha protein expression in rat skeletal muscle

2005 ◽  
Vol 184 (1) ◽  
pp. 59-65 ◽  
Author(s):  
S. Terada ◽  
K. Kawanaka ◽  
M. Goto ◽  
T. Shimokawa ◽  
I. Tabata
Keyword(s):  
Skeletal Muscle ◽  
Protein Expression ◽  
High Intensity ◽  
Rat Skeletal Muscle

scholarly journals Antioxidants Facilitate High–intensity Exercise IL–15 Expression in Skeletal Muscle

2018 ◽  
Vol 40 (01) ◽  
pp. 16-22 ◽  
Author(s):  
Alberto Pérez-López ◽  
Marcos Martin-Rincon ◽  
Alfredo Santana ◽  
Ismael Perez-Suarez ◽  
Cecilia Dorado ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Expression ◽  
High Intensity ◽  
Human Skeletal Muscle ◽  
Vastus Lateralis ◽  
Acute Hypoxia ◽  
High Intensity Exercise ◽  
Oxygen Deficit ◽  
Post Exercise ◽  
Sprint Exercise

AbstractInterleukin (IL)-15 stimulates mitochondrial biogenesis, fat oxidation, glucose uptake and myogenesis in skeletal muscle. However, the mechanisms by which exercise triggers IL-15 expression remain to be elucidated in humans. This study aimed at determining whether high-intensity exercise and exercise-induced RONS stimulate IL-15/IL-15Rα expression and its signaling pathway (STAT3) in human skeletal muscle. Nine volunteers performed a 30-s Wingate test in normoxia and hypoxia (PIO2=75 mmHg), 2 h after placebo or antioxidant administration (α-lipoic acid, vitamin C and E) in a randomized double-blind design. Blood samples and muscle biopsies (vastus lateralis) were obtained before, immediately after, and 30 and 120 min post-exercise. Sprint exercise upregulated skeletal muscle IL-15 protein expression (ANOVA, P=0.05), an effect accentuated by antioxidant administration in hypoxia (ANOVA, P=0.022). In antioxidant conditions, the increased IL-15 expression at 120 min post-exercise (33%; P=0.017) was associated with the oxygen deficit caused by the sprint (r=–0.54; P=0.020); while, IL-15 and Tyr705-STAT3 AUCs were also related (r=0.50; P=0.036). Antioxidant administration promotes IL-15 protein expression in human skeletal muscle after sprint exercise, particularly in severe acute hypoxia. Therefore, during intense muscle contraction, a reduced PO2 and glycolytic rate, and possibly, an attenuated RONS generation may facilitate IL-15 production, accompanied by STAT3 activation, in a process that does not require AMPK phosphorylation.

scholarly journals Lifelong strength training mitigates the age-related decline in efferent drive

2016 ◽  
Vol 121 (2) ◽  
pp. 415-423 ◽  
Author(s):  
Runar Unhjem ◽  
Mona Nygård ◽  
Lene T. van den Hoven ◽  
Simranjit K. Sidhu ◽  
Jan Hoff ◽  
...  
Keyword(s):  
Strength Training ◽  
Plantar Flexion ◽  
H Reflex ◽  
Voluntary Activation ◽  
M Wave ◽  
Reflex Amplitude ◽  
Age Related ◽  
Musculus Soleus ◽  
V Wave ◽  
Voluntary Contractions

Recently, we documented age-related attenuation of efferent drive to contracting skeletal muscle. It remains elusive if this indication of reduced muscle strength is present with lifelong strength training. For this purpose, we examined evoked potentials in the calf muscles of 11 [71 ± 4 (SD) yr] strength-trained master athletes (MA) contrasted with 10 (71 ± 4 yr) sedentary (SO) and 11 (73 ± 6 yr) recreationally active (AO) old subjects, as well as 9 (22 ± 2 yr) young controls. As expected, MA had higher leg press maximal strength (MA, 185 ± 32 kg; AO, 128 ± 15 kg; SO, 106 ± 11 kg; young, 147 ± 22 kg, P < 0.01) and rate of force development (MA, 5,588 ± 2,488 N/s; AO, 2,156 ± 1,100 N/s; SO, 2,011 ± 825 N/s; young, 3,663 ± 1,140 N/s, P < 0.05) than the other groups. MA also exhibited higher musculus soleus normalized V waves during maximal voluntary contractions (MVC) [maximal V wave amplitude/maximal M wave during MVC (Vsup/Msup); 0.28 ± 0.15] than AO (0.13 ± 0.06, P < 0.01) and SO (0.11 ± 0.05, P < 0.01), yet lower than young (0.45 ± 0.12, P < 0.01). No differences were apparent between the old groups in H reflex recorded at rest or during MVC [maximal H reflex amplitude/maximal M wave during rest (Hmax/Mmax); maximal H reflex amplitude during MVC/maximal M wave during MVC (Hsup/Msup)], and all were lower ( P < 0.01) than young. MA (34.4 ± 2.1 ms) had shorter ( P < 0.05) H reflex latency compared with AO (36.4 ± 3.7 ms) and SO (37.3 ± 3.2 ms), but longer ( P < 0.01) than young (30.7 ± 2.0 ms). Using interpolated twitch analysis, MA (89 ± 7%) had plantar flexion voluntary activation similar to young (90 ± 6%), and this was higher ( P < 0.05), or tended to be higher ( P = 0.06–0.09), than SO (83 ± 10%) and AO (84 ± 5%). These observations suggest that lifelong strength training has a protective effect against age-related attenuation of efferent drive. In contrast, no beneficial effect seems to derive from habitual recreational activity, indicating that strength training may be particularly beneficial for counteracting age-related loss of neuromuscular function.

Different skeletal muscle HSP70 responses to high-intensity strength training and low-intensity endurance training

2004 ◽  
Vol 91 (2-3) ◽  
pp. 330-335 ◽  
Author(s):  
Yuefei Liu ◽  
Werner Lormes ◽  
Liangli Wang ◽  
Susanne Reissnecker ◽  
J�rgen M. Steinacker
Keyword(s):  
Skeletal Muscle ◽  
Strength Training ◽  
Endurance Training ◽  
High Intensity ◽  
Low Intensity

scholarly journals Efectos de entrenamiento de fuerza en sistema isoinercial sobre la mejora del CMJ en jóvenes futbolistas de elite (Effects of strength training using a isoinertial device on jump ability in young elite soccer players)

Retos ◽  
2015 ◽  
pp. 180-182
Author(s):  
Sergio Romero Boza ◽  
Adrián Feria Madueño ◽  
Borja Sañudo Corrales ◽  
Moisés De Hoyo Lora ◽  
Juan José Del Ojo López
Keyword(s):  
Strength Training ◽  
Force Production ◽  
Team Sport ◽  
Soccer Players ◽  
Maximal Strength ◽  
Countermovement Jump ◽  
Palabras Clave ◽  
Jump Ability ◽  
Physical Skills

El fútbol es un deporte colectivo donde, para alcanzar el éxito, los jugadores necesitan de habilidades técnicas, tácticas y físicas, fundamentalmente de carácter intermitente siendo éstas acciones las que determinan el rendimiento. Un ejemplo de acciones de este tipo son los saltos. Este gesto deportivo esta correlacionado con la fuerza máxima, entendiendo que una mayor producción de fuerza permite una mayor generación de altura en dicho gesto. El objetivo de este trabajo es estudiar el efecto de entrenamiento de fuerza en sistema isoinercial sobre la mejora del Salto con Contramovimiento y analizar los cambios en la altura del mismo después de un programa de entrenamiento de 15 semanas, realizado sobre jóvenes futbolistas de élite. Los resultados obtenidos, muestran que no existen cambios significativos en esta variable de análisis (p< 0,05) por lo que se concluye que este tipo de entrenamiento con la duración especificada no tiene efectos sobre el rendimiento en la altura del salto (CMJ).Palabras clave: Entrenamiento Isoinercial, Futbolistas, Rendimiento, CMJ.Abstract: Soccer is a team sport where, to achieve success, players need of technical, tactical and physical skills, mainly intermittent character being such actions which determine the performance. An example of such actions is the jumpers. This sports actions is correlated with the maximal strength, understanding that force production allows greater height in this actions. The aim is to study the effects of strength training using a isoinertial device on Countermovement Jump ability and to analyze the changes in height after 15 weeks program training in young elite soccer players. There are no significant changes after to analyze the results (p< 0,05), so it is concluded that this type of training with certified duration has no effect on performance in height jump (CMJ).Keywords: Isoinertial Training, Soccers Players, Performance, CMJ.

High-intensity strength training in nonagenarians. Effects on skeletal muscle

JAMA ◽  
1990 ◽  
Vol 263 (22) ◽  
pp. 3029-3034 ◽  
Author(s):  
M. A. Fiatarone
Keyword(s):  
Skeletal Muscle ◽  
Strength Training ◽  
High Intensity

Increased spinal reflex excitability is not associated with neural plasticity underlying the cross-education effect

2006 ◽  
Vol 100 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Olle Lagerquist ◽  
E. Paul Zehr ◽  
David Docherty
Keyword(s):  
Strength Training ◽  
Plantar Flexion ◽  
Exercise Group ◽  
H Reflex ◽  
Spinal Reflex ◽  
Control Group ◽  
M Wave ◽  
Education Effect ◽  
Cross Education ◽  
The Cross

The purpose of this study was to examine the effects of a 5-wk unilateral, isometric strength-training program on plasticity in the spinal Hoffmann (H-) reflex in both the trained and untrained legs. Sixteen participants, 22–42 yr old, were assigned to either a control ( n = 6) or an exercise group ( n = 10). Both groups were tested for plantar flexion maximal voluntary isometric contractions (MVIC) and soleus H-reflex amplitude in both limbs, at the beginning and at the end of a 5-wk interval. Participants in the exercise group showed significantly increased MVIC in both legs after training ( P < 0.05), whereas strength was unchanged in the control group for either leg. Subjects in the exercise group displayed increased ( P < 0.05) H-reflex amplitudes on the ascending limb of the recruitment curve (at an equivalent M wave of 5% of the maximal M wave, HA) only in the trained leg. Maximal H-reflex and M-wave remained unchanged with training. Increased amplitude of HA in the trained limb concurrent with increased strength suggests that spinal mechanisms may underlie the changes in strength, possibly because of increased α-motoneuronal excitability or reduced presynaptic inhibition. Despite a similar increase in strength in the contralateral limb of the exercise group, HA amplitude was unchanged. We conclude that the cross-education effect of strength training may be due to supraspinal to a greater extent than spinal mechanisms.

scholarly journals Enhanced neural drive after maximal strength training in multiple sclerosis patients

2010 ◽  
Vol 110 (2) ◽  
pp. 435-443 ◽  
Author(s):  
Marius S. Fimland ◽  
Jan Helgerud ◽  
Markus Gruber ◽  
Gunnar Leivseth ◽  
Jan Hoff
Keyword(s):  
Multiple Sclerosis ◽  
Strength Training ◽  
Maximal Strength ◽  
Neural Drive ◽  
Multiple Sclerosis Patients
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