2.4 Thresholds of Training

Last Lesson…. Aerobic respiration = Produces energy using oxygen. Anaerobic respiration = Produces energy without using oxygen Most sports are a mixture of aerobic and anaerobic work. Every time the anaerobic system is used lactic acid builds up. At some point extra oxygen will be needed to get rid of it- this is called oxygen debt...

Oxygen Debt Oxygen debt is defined as the amount of oxygen required to get the body back to it’s resting state. Most of the lactic acid gets turned into carbon dioxide (which we breath out) and water, while a small amount gets turned into glucose when enough oxygen is available.

Oxygen Debt An oxygen debt can come from:  Any maximum effort activities. The hard breathing you do immediately after all out effort is you taking in extra oxygen to repay the debt.  During long events eg. Long distance running and cycling. At the beginning of the exercise while waiting for heart rate and breathing to increase to get oxygen to working muscles.  Any sports that require a sudden burst of speed or max effort. Eg. Team sports, long distance running, when trying to lose an opponent or finish strongly.

Energy systems and heart rate Heart rate can help show how hard we are working and which energy system we are using. Your heart rate will eventually get to a point when it can’t beat any faster. This is called maximum heart rate. This can be estimated by using the formula: Maximum heart rate=220- your age At 15 your max heart rate is 205 beats per minute. If your pulse rate is around 60% of maximum, you are working aerobically. If it is around 90%, you will be working anaerobically.

Heart rate and target zones Depending on how fit you want to be, what energy systems you want to train and how fit you currently are, you need to work within a range of heart rates. This is a target zone. Label the graph below

To gain aerobic fitness… You must exercise above a minimum heart rate. Your minimum rate depends on how fit you are. For an unfit 15 year old it is about 60% of your max HR. If you exercise below this you won’t get aerobic benefits. You must also exercise below an upper limit. Once your heart rate rises above a certain point you are working anaerobically and lactic acid will build up. This point is somewhere between % of maximum

Look at second graph in text book. This is for a 15 year old- so it’s relevant for grade 9 students. An unfit person should be working at 60-70% of maximum HR, a person of average fitness at 65-75% and a fit person at 75-85%. This will be important when planning your training program.

Questions 1-4 on from chapter 2.4