Endurance training is the deliberate act of exercising to increase stamina and endurance, this tends to be aerobic in nature and develops slow twitch muscles. Aerobic fitness levels are dependant upon the amount of oxygen which can be transported by the body to the muscles and the efficiency of the muscles to use this oxygen. Aerobic exercises will strengthen and elongate the muscles enabling them to work for longer periods of time. Elongating the muscles improves the muscles elasticity, resulting in increased muscle control, increased range of motion and flexibility. Stretching before a workout will help elongate the muscles, which in turn will reduce the chance of injury and increase performance. Stretching is itself an art form and when performed incorrectly can be dangerous and cause permanent damage to tendons, ligaments and muscle fibres, to learn how to stretch correctly you should consider taking a yoga class. Yoga is not just important for stretching but also for attaining ultimate focus and since a steady heart rate can only be achieved by a conditioned body and focused mind, yoga should be a must in your training repertoire.
Endurance training over time, will train your body to use oxygen more efficiently, enhancing the way the muscles and cardiovascular system work. You will also benefit from increased energy levels, a strengthened immune system and healthy blood pressure. Further to this your body will be encouraged to use fat as the preferred fuel, fat is utilized for fuel only when lactate is absent, once lactate starts to accumulate fat utilization is impaired.
Vo2Max
The test for aerobic fitness is known as the Vo2Max test or the ’maximal oxygen uptake’. This is defined as being the highest rate of oxygen which can be taken up and utilised by the body during severe exercise ( Basset and Howley 2000) Vo2Max is measured as millilitres of oxygen used in one minute per kilo of body weight and is usually calculated in a laboratory by a professional, however there is a way you can calculate an approximate Vo2Max for yourself. Row 2000m in your quickest time then add your weight, age and gender to the equation. The following table is the work of Dr Fritz Hagerman of Ohio University USA, use this to determine your Vo2Max.
| Cardiovascular Fitness Calculations Based on VO2max (mL*kg-1*min-1) | ||||||
|---|---|---|---|---|---|---|
| Gender | Age | Poor | Fair | Average | Good | Excellent |
| Men | <=29 | <=24.9 | 25-33.9 | 34-43.9 | 44-52.9 | >=53 |
| 30-39 | <=22.9 | 23-30.9 | 31-41.9 | 42-49.9 | >=50 | |
| 40-49 | <=19.9 | 20-26.9 | 27-38.9 | 39-44.9 | >=45 | |
| 50-59 | <=17.9 | 18-24.9 | 25-37.9 | 38-42.9 | >=43 | |
| 60-69 | <=15.9 | 16-22.9 | 23-35.9 | 36-40.9 | >=41 | |
| Women | <=29 | <=23.9 | 24-30.9 | 31-38.9 | 39-48.9 | >=49 |
| 30-39 | <=19.9 | 20-27.9 | 28-36.9 | 37-44.9 | >=45 | |
| 40-49 | <=16.9 | 17-24.9 | 25-34.9 | 35-41.9 | >=42 | |
| 50-59 | <=14.9 | 15-21.9 | 22-33.9 | 34-39.9 | >=40 | |
| 60-69 | <=12.9 | 13-20.9 | 21-32.9 | 33-36.9 | >=37 | |
The formula used to find your Vo2Max is Vo2 = (Y*1000/weight). The * represents the multiplication sign and your weight is in kilos.
For men training at a high intensity level the following formulas are required to find Y:- Weight - less than 75kg: Y = 15.1-(1.5*time) Weight - more than 75kg: Y = 15.7-(1.5*time)
For women training at high intensity levels the following formula is required to find Y:- Weight - less than 61.36kg Y = 14.6(1.5*time) Weight - more than 61.36kg Y = 14.6(1.5*time)
For both men and women training at low intensity levels the following formulas are required to find Y:-
Men - Y = 10.7-(0.9*time) Women - Y = 10.26-(0.93*time)
N.B - Time is the pace converted to minutes.
If you have a low Vo2Max it simply means that you need to inhale more oxygen to perform your workout, this is due to the inefficiency of your lungs when transporting the oxygen via the bloodstream to the muscles. If this is the case you need to condition your lungs and increase their capacity. Lung capacity varies according to gender (women tend to have 20-25% lower capacity than men), height, age, weight and obviously degree of physical activity are also factors. The Framingham Heart Study found that ’the bigger that your lungs are the longer your life will be’ It is apparent from this statement that aerobic exercise is crucial to the longevity of life. You can increase your lung capacity in various ways, by taking up yoga for breathing exercises, using a breathing exerciser - which simulates playing an instrument, running at high altitudes - for the serious athlete, as well as general aerobic training. Also, in a swimming pool, try walking under water as far as you can across the pool. Once you have started to increase lung capacity through one or more of the above, it is important to maintain a high exercise economy by perfecting technique, stride length and body positioning during training.
Maximum Heart Rate And Rate Of Perceived Exertion
Heart rate is the number of heartbeats per unit of time, measured as beats per minute (bpm). Monitoring your heart rate will enable you to attain maximum efficiency from your workout, maximum heart rate (MHR) can be calculated using the formula:- MHR = 220-age
Research conducted by Dr Martha Gulati found a different formula should be applied when trying to estimate the MHR in women:- MHR = 206.3-(0.711*age)
It is also possible to estimate your exercise intensity as a percentage of Vo2Max from your training heart rate. The following formula was created by David Swain and his US based research team in 1994:- %MHR = 0.64*%Vo2Max+37. This formula is the same for both men and women and isn’t age or activity sensitive.
If you are a newcomer to endurance training you should start off performing low intensity aerobic activity and keep within a 50-65% range of your maximum heart rate. As your stamina increases you should be working at up to 80% of your MHR.
The rate of perceived exertion is a subjective evaluation of how hard your body is working during training, it is a self assessment tool for your own benefit and usually comes in the form of the Borg scale. When assessing yourself you need to take into consideration all of the physiological aspects of your workout to ascertain where on the scale of perceived exertion you are at any given time during your workout. You must factor in how hard your heart and lungs are working, how much energy you feel you have to exert to keep on going, how your muscles and joints are feeling during training and how much you sweat. Take all these factors into consideration and assign a point value to them, find your value on the Borg scale to determine how hard you are working. The following table shows the Borg scale:
It is normally recommended that you stay at around level 13-14 for beginners trying to burn fat and that you keep above level 15 if you are an endurance athlete. During training, rises in RPE can also be attributed to emotional state, mental focus, form deterioration and accumulation of metabolic waste products. There is a close correlation between RPE and MHR, for example if you multiply your Borg score by 10 you should find that it will be approximately the same as your heart rate. However if you develop your mental focus (yoga and meditation) and your strength (weight training) you wont experience a correlating rise in heart rate.
Aerobic And Anaerobic Thresholds
The first 60 seconds or so of endurance training sees the body using ATP as the main source of energy (for muscular contraction). After this oxygen becomes the main energy source as the body starts to use the aerobic system. During aerobic work the body is working at a level that the demand for oxygen and fuel can be easily met by the bodys intake and the ability of the cardiovascular system to transport this oxygen to the muscles. Once your body is working at around 65% of your maximum heart rate anaerobic pathways start to operate, it is at this point you are at the aerobic threshold and oxygen is no longer utilised to create ATP. You will experience an increase in the depth of breathing and a sense of moderate effort intensity, but should battle on as challenging your aerobic threshold is vital for complete aerobic development. Most people make the mistake of just sticking to long, slow distance training, therefore not challenging their aerobic threshold at all, it is important to do both.
During anaerobic work the body is working at such a rate that the demand for oxygen and fuel exceeds the rate of supply and the muscles are solely reliant on the bodys fuel reserves. At this point the oxygen starved muscles force the body into a state known as 'oxygen debt' and lactic acid starts to accumulate in the muscles. At high intensity training your lactic acid levels will rise uncontrolably resulting in muscle failiure, this is your lactate or anaerobic threshold (the wall) and it will vary from person to person. In order to continue training the lactic acid must be removed and the oxygen debt repaid. Short rest periods will enable you to resume training for limited time as the oxygen debt is slowly repaid and the body begins to work anaerobically without the production of lactic acid, this is known as the lactic anaerobic pathway. This pathway is dependant on the fuel stored in the muscle (glycogen) and the larger the muscle the more glycogen it will contain, allowing training to continue for longer, although without sufficient rest this will only really be for a matter of seconds rather than minutes. When glycogen stores are depleted lipolysis kicks in and triacylglycerol (fat) is used as a source of energy.
The key to endurance training is fairly evident, you need to work below the lactate threshold in order to train for longer periods, thus you need to increase this threshold. Through correct training the onset of lactic acid build up can be delayed, this training should be in the form of interval and tempo running. It is worth noting that the lactate threshold for the beginner will be reached at around 60% of Vo2Max and that training can improve that to 65-80% of Vo2Max. You need to be patient with your endurance training as it can take anywhere between 8-12 weeks to develop a strong aerobic base
Eating For Endurance
Endurance exercise uses muscle glycogen, blood glucose (and fatty acids) to fuel performance, these substrates are provided to the body through the digestion of carbs. As exercise intensity increases, more and more carbs are used up and as supplies diminish the body turns to stored fats for fuel. The problem here is that fats aren't as easily metabolised as carbs and the process is far more oxygen costly, meaning exercise intensity will diminish. Carb loading before an event or an intense workout will boost the body's glycogen stores, providing greater fuel for the latter stages of the event or workout.
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