(Poly)phenols in Exercise Performance and Recovery
James N. Cobley, Gareth W. Davison in Oxidative Eustress in Exercise Physiology, 2022
To examine the effects of (poly)phenols on exercise recovery, many studies have utilised a model that evokes significant muscle damage. This is usually characterised by exercise that has a substantial eccentric muscle contraction (i.e., the muscle lengthening under tension) component and/or is of a long duration or high intensity. However, there are examples where the exercise challenge is metabolically taxing (cycling) but has little or no eccentric component (Bell et al., 2014a, 2015). Other examples include recovery from marathon running (Howatson et al., 2010), intermittent sprint sports (Bell et al., 2016) and resistance exercise (Connolly, McHugh and Padilla-Zakour, 2006; Trombold et al., 2010; Bowtell et al., 2011). It is unlikely that (poly)phenol interventions will reduce the magnitude of mechanical damage on the skeletal muscle myofilaments, but given the putative antioxidative and anti-inflammatory properties of many (poly)phenols (via the above-described mechanisms), it makes the expectation tenable that exercise-induced increases in RONS and/or inflammation could be attenuated and help return function at an accelerated rate (Howatson and van Someren, 2008; Bell et al., 2014b). We provide some cursory examples to illustrate the potential benefits of (poly)phenols in exercise recovery.
Electromyograms
A. Bakiya, K. Kamalanand, R. L. J. De Britto in Mechano-Electric Correlations in the Human Physiological System, 2021
In the measurement of EMG signals, there are two categories of contractions, namely, isotonic contraction and isometric contraction (Nazmi et al., 2016). Isotonic contraction is often used for athletic goals, whereas isometric contractions are utilized for physical rehabilitation. The isotonic contraction is a muscle contraction that produces force with respect to the resistance in which the length of the muscle changes. Further, isotonic contraction is classified into two types, namely, the concentric contraction and eccentric contraction (Nazmi et al., 2016). The combination of concentric and eccentric contraction creates a dynamic contraction (e.g., the joint movement during dumbbell bicep curl exercise). Concentric contraction permits the muscle to reduce unstable energy but rigidity remains constant during the contraction. In eccentric contraction, the length of the contraction is longer, disturbing the muscles to stretch in response to a greater opposing force. Isometric contraction is the contraction that creates no change in muscle length but the energy and tension remain unstable (Nazmi et al., 2016).
Muscle Physiology and Electromyography
Verna Wright, Eric L. Radin in Mechanics of Human Joints, 2020
A muscle contraction is the result of an electrical impulse from the CNS arriving at the motor unit. This impulse can be detected as a potential difference between a pair of recording electrodes either on the surface of the skin above the muscle or inserted into the muscle itself (21). If a microelectrode is placed within a muscle fiber and another on the outside of the fiber, the potential detected from the inside of the fiber is negative relative to the outside. This is the resting potential of the fiber (22,23). As a wave of depolarization passes along the fiber, the potential of the inside of the fiber relative to the outside becomes positive as more positively charged ions enter as a result of permeability changes. These changes in cell polarity are detected by the electrodes; the information is passed to an amplifier for processing and filtering and finally to an output device (oscilloscope, pen recorder, or computer) for display (see Fig. 11). With sensitive equipment, even a minor muscle contraction produces a reasonable EMG record.
Dual-Task Training Effects on the Cognitive-Motor Interference in Individuals with Intellectual Disability
Published in Journal of Motor Behavior, 2023
Rihab Borji, Thoraya Fendri, Sofien Kasmi, Emna Haddar, Rabeb Laatar, Sonia Sahli, Haithem Rebai
Isometric muscle force for the quadriceps muscle group of the dominant leg was assessed before and after the 8 weeks only under ST condition. Participants were asked to perform 3 MVC of the knee extensors lasting 5 s with a 3-min rest period between trials. Strong verbal encouragements were provided to the participants during all of these MVC. In the beginning of the testing session, participants performed many (12-15) sub-maximal isometric contractions as a warm-up phase. Participants were seated comfortably on a knee extension device (leg extension machine, PANATTA SPORT ®, Italia) with the trunk-thigh angle flexed at 90°. A strap secured the hips and thighs to minimize uncontrolled movements. The force generated during the muscle contraction was assessed by a strain gauge. A leather ankle cuff was placed around the dominant leg just proximal to the malleoli and tightly attached to a load cell (range 0–2500 N; Globus Ergometer, Globus, Codogne, Italy) properly mounted on the leg extension machine. The chain was adjusted in length so that when the participant performed knee extension, the knee remained at 90° of flexion (0° corresponds to full knee extension). The signal from the load cell was amplified using a Globus amplifier (Tesys 400, Globus, Codogne, Italy) and fed through an analog-todigital converter (12 bit) and stored on computer with a sampling frequency of 1000 Hz.
Impact of methionine restriction on muscle aerobic metabolism and hypertrophy in young and old mice on an obesogenic diet
Published in Growth Factors, 2022
Anandini Swaminathan, Leonardo Cesanelli, Tomas Venckunas, Hans Degens
Mitochondria play a vital role in cellular ATP production, necessary for muscle contraction and viability of muscle cells. The mitochondrial dysfunction during ageing may impinge on proteostasis and result in a loss of muscle mass and function (Bellanti, Lo Buglio, and Vendemiale 2021), and may occur as a result of increased reactive oxidative species (ROS) production and lowered antioxidant defences (Miquel et al. 1980; McCormick and Vasilaki 2018). The low-grade systemic inflammation induced by obesity and old age, combined with deteriorated mitochondrial function, is especially relevant to older obese adults who have higher levels of muscular fat infiltration (Choi et al. 2016). Calorie restriction and exercise have been shown to delay the ageing- and obesity-associated impairment of mitochondrial function (Bhatti, Bhatti, and Reddy 2017; Ruetenik and Barrientos 2015). Similarly, it has been observed that while there was an absence of mitochondrial biogenesis, there was an increase in mitochondrial oxidative capacity in skeletal muscle of young-adult rats fed a MR diet (Perrone et al. 2010). Whether this increase in mitochondrial capacity in skeletal muscle after MR extends to old age and obesity is yet to be elucidated.
Resistance training using different elastic components offers similar gains on muscle strength to weight machine equipment in Individuals with COPD: A randomized controlled trial
Published in Physiotherapy Theory and Practice, 2022
Ana Paula Coelho Figueira Freire, Carlos Augusto Marçal Camillo, Bruna Spolador de Alencar Silva, Juliana Souza Uzeloto, Fabiano Francisco de Lima, Luis Alberto Gobbo, Dionei Ramos, Ercy Mara Cipulo Ramos
The increment in the ETG and EBG was done by changing the diameter of the tubes/color of the band and/or adding extra tubes/bands. Since the load was adjusted according to subject´s effort in each week, the progression of the load was individualized and can be seen in the results section of the study. Estimative of load for elastic components (i.e. tubing and bands) was based on previous literature and research studies (American Physical Therapy Association, 1999; Lima et al., 2019). Increases in the workload for participants in the CG followed the same criterion of ETG with changes in the weights of the machine. This protocol was based on previous studies (Persch, Ugrinowitsch, Pereira, and Rodacki, 2009; Silva et al., 2016) and an explanatory figure for intervention modalities can be seen in Figure 1. Velocity of muscle contractions was controlled by the therapist to last approximately 2 s in both concentric and eccentric component of the exercise. Between each set of training, participants were instructed to rest for 2 min.
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