The Role of Central Fatigue in Resistance and Endurance Exercises

Oxygen debt in the muscles is reached when oxygen levels are much lower than required during strenuous physical activity, causing lactate fermentation to occur in the cells leading to muscle fatigue. The results found in the experiment were the number of squeezes in the first trial for the dominant and non-dominant hands were significantly higher than the remaining ones. The results also showed as the trials continued, the number of muscle contractions decreased steadily which supported the hypothesis. However, there were some increased numbers for the dominant hand from trial 4 to 5 and trial 9 to 10. The non-dominant hand expressed similar unexpected results from trial 6 to 7 and trial 9 and 10. The reasons for these results might be due to the finger muscles being worked at the high intensity for a long period of time causing the muscles to consume higher amounts of oxygen thus producing more ATP production. This would cause the muscles to create more contractions towards the end of the trials. The unexpected results could also be caused by experimental errors such as faulty clothespins. The springs connecting the two ends of the clothespin was tight causing the number of contractions as the trials progressed having a more significant decrease. This is because the amount of energy required to open and close the clothespin would be higher, causing the lactate threshold to occur quicker. Due to this, the number of squeezes would decrease drastically as the trials progressed, in contrast to if the springs were normal. This would change the results by the difference between the trials not being evident therefore, not demonstrating the effects of muscle fatigue. Another factor that altered this experiment was the participant’s condition, Palmar Hyperhidrosis –excessive sweating on the palms – which

For example many people will show an improvement in strength from the first session to the second session. This improvement is due to CNS adaptation because there is no hypertrophic gain during this short period. Another example which proves the importance of CNS adaptations related to strength gains is that strength performance may increase by 30% while hypertrophic gains may only be 15%, thus half of the strength gains is attributable to CNS adaptations. Generally in the first few months of strength training CNS adaptations account for a larger percentage of the strength gain than hypertrophic adaptations. To illustrate the importance of CNS adaptations in the early part of training, it should be noted that electrical stimulation can increase the rate of strength gains. Hypertrophy is an important factor in improved strength performance. Strength training brings about an increase in the size and number of myofibrils. It is speculated that during and following a high intensity strength training session the neuroendocrine responses will bring about an increased amino acid uptake and will increase the rate of protein synthesis. Optimal hypertrophic gains require adequate recovery between workouts to permit the rate of protein synthesis to exceed the rate of protein degradation. It should also be noted that strength training also stimulates bone and

I know that the more times I skip, lactic acid will build up in my legs, from my own experience this makes you fell horrible. As our bodies perform strenuous exercise, we begin to breathe faster as we attempt to move more oxygen to our working muscles. The body prefers to generate most of its energy using aerobic methods, meaning with oxygen. The cells follow the aerobic process when the blood supplies enough oxygen to the cells, which is:- Glucose+ oxygen—>Carbon Dioxide+ water+ Energy. But when the blood cannot get the needed oxygen to the cells, it has to get the energy from the glucose in another way. The cells use the anaerobic pathway; It does this then by breaking glucose down into lactic acid, Glucose—>Lactic Acid+ Energy. Lactic acid is released into the muscles when they have used up glucose stores but still have intense energy needs. Small amounts of lactic acid operate as a temporary energy source, which helps you avoid fatigue during a workout. However, a build-up of lactic acid during a workout can create burning sensations in the muscles that can slow down or halt your activity. This is not an effective energy source for long periods of exercise, so the blood takes lactic acid to the liver which coverts it back into glucose to be used in the normal aerobic process. Scientist are always looking into ways to decrease lactic acid build up in elite athletes so they can perform faster

Nelson Cortes, Eric Greska, Roger Kollock, Jatin Ambegaonkar, and James A. Onate (2013) Changes in Lower Extremity Biomechanics Due to a Short-Term Fatigue Protocol. Journal of Athletic Training: May/Jun 2013, Vol. 48, No. 3, pp. 306-313

Every time our body moves, our muscles contract. As the muscle contracts, the muscle becomes fatigued; unable to maintain force output. There are two types of fatigue; central and peripheral (1). Central fatigue involves the central nervous system, whereas peripheral fatigue includes fatigue outside of the central nervous system in the muscles (5). Changes to these systems affect the rate at which the muscle fatigues, including the speed of contraction, the strength of the load, and feedback (5). Therefore, the purpose of this study was to determine whether increased force would influence the time of fatigue, with and without visual feedback. It was hypothesized that as the magnitude of force increased, the time to fatigue would decrease, whereas while the magnitude of force decreased, the time to fatigue would increase. Overall, visual feedback would have increased time to fatigue, compared to non-visual feedback, which would have decreased time to fatigue.

(1993), investigating the effects of moderate intensity exercise training on four older individuals on muscle energy utilization, blood flow, and exercise performance. For 12 weeks, each subject trained their dominant arm each day, while their non-dominant arm was served as a control and was not trained. A 31P nuclear magnetic resonance spectroscopy was used to detect the power output the threshold of intracellular acidosis (IT) to test for fatigue. IT increased 14% on the dominant arm after 6 weeks of training, but there weren’t further increases in IT. Power increased 34% at 6 weeks and 58% at 12 weeks. The training delayed fatigue form IT and increased the capacity for submaximal work and did not depend of muscle blood

Even when you do not think your muscles are at work, they are. Muscles are in your heart too. Muscles are hard workers. Fatigue during intense workouts is connected to the anaerobic metabolism for force production that muscles rely on so much. As your muscles use up the ATP while exercising, they become fatigued and tired. You can do aerobic exercises longer because while you are using ATP, oxygen is helping create more. But Anaerobic exercises are more intense but shorter workouts. As ATP starts to run out during these types of workouts, your muscles start to produce acidosis. This is why sometimes your muscles burn during workouts. Lactase then comes in to reduce the acidosis and in result, creates ATP. So why working out, you create more ATP. Sometimes your working so hard and so fast that the oxygen that is trying to help create ATP is too slow and that is why you get tired and have to take a break to catch up. Often why you have cool downs after high intensity workouts to get more oxygen in your body to perform better and recover faster.

When challenged, the body adapts to extended muscle use. With sufficient resources, it attempts to strengthen the muscle. Our bodies alert us of this process through fatigue. Pain alerts us of an injury to the muscle.

These can range from lifting very heavy weights, to intricate tasks such as playing a piano, to pumping blood non-stop for a lifetime. To accommodate such wide variation, muscles have high plasticity and can adapt to changing activity levels and environments. For example, endurance exercise increases the oxidative capacity and makes muscle more fatigue resistant while disuse leads to muscle atrophy [1]. The pathways underlying these changes and muscle plasticity are therefore of great interest.

Not only is muscle fatigue and muscle recovery affected there are many other physiological factors that are affected as well. These physiological factors play a major role in athletic training and must be maintained if athletic performance is expected to stay at a high level. A few of these factors are VO2 max, maximal heart rate, stroke volume, economy of movement, and aerobic enzyme activity. (Reaburn) Many of these elements play a smaller role in accounting for and culminating to another one. An example of this would be how stroke volume, muscle mass, and aerobic enzyme activity play a major role in the process of VO2 max. When you observe a decrease in all of these things you will see that there will be a major decrease in the athlete’s

Muscle fatigue is defined as a decrease in the maximum force generating capacity of a muscle (3). Muscle force and fatigability are correlated to muscle mass, muscle fiber type, and motor unit recruitment. Muscle fibers consume stored energy and generate force by contracting. If a muscle depletes its fuel supply faster than they can be replenished by metabolism, then fatigue occurs. The purpose of this study was to determine the time to fatigue to 50% of maximum clench force for both dominant and non-dominant arms, and then determine differences between male and female. Recent literature has suggested that there are sex differences in muscle fatigability, however the physiological mechanisms are not entirely understood. In general, men have

Training is a very important factor when it comes to athletes improving their overall performance. If an athlete trains very lightly, then there will be no results showing improvement. If an athlete trains hard, they are left with underperformance, but if proper recovery is allowed, there will be improving results. Every athlete trains with intensity in hopes of improving their day to day performance. But training intense will not always bring beneficial factors. Training too often without adequate rest can bring serious effects to the human body. “The overtraining syndrome is a condition of fatigue and underperformance, often associated with frequent infections and depression which occurs following hard training and competition” (Budgett 1).

This article is about overreaching and overtraining during exercise. Overreaching is broken down into two states: functional and nonfunctional. Non functional overreaching results in decreased performance, while functional overreaching deals with neuroendocrine and or psychological symptoms. Both states respond to extra rest. As a result to non functional overreaching, overtraining causes prolong performance decrement and more severe systems. This lasts up to two months or more. To prevent overreaching/overtraining, you must have an effective conditioning program that requires a balance between intense training sessions and periods of rest/recovery. Too much overload and not enough recovery, results in physiological and psychological symptoms.

The outcomes of the study ware general bodily pain which was measured using visual analogue scale[6], after 12 weeks of training shows non-significant change with a p-value of ( 0.280). The second outcome was muscle strength, a calibrated handheld dynamometer was used to measure the maximum isometric strength of knee extension[9], and showed a significant improvement in muscle strength after 12 weeks of training with a p-value of(0 .001). Bodily pain

To prevent confounding, several training variables detailed below were controlled in both groups. Participants followed a training frequency of three RT sessions per week, undertaken on the same, non-consecutive days, allowing approximately 48 hours between RT sessions to provide adequate recovery and reduce the effects of delayed onset muscle soreness. Sessions also occurred at the same facilities (Monday & Friday: Broadwood Stadium, Wednesday: Ravenscraig Regional Sports Facility), at the same time of day (18:30-19:30), to reduce circadian fluctuations and under the same environmental conditions (18-21°C) to minimise the impact of temperature on