Exercise physiology Preparation & training methods training intensity Learning Objective: To be able to explain how and why exercise intensity levels are measured 2.2.7 There are also different ways of measuring and calculating intensity. 2.2.8 Target heart rate: understanding and use of Karvonen’s theory. 2.2.9 Contemporary technology for tracking fitness and measuring intensity.

Measuring Exercise Intensity Intensity of training can be measured using: 1 Rep max Maximum Heart Rate Karvonen’s Theory Borg Scale British cycling exercise intensity levels

1 Rep Max ‘The maximum amount of weight an individual can lift in a single repetition for a given exercise.’ When an individual knows their 1 rep max they can then work at a percentage of that to ensure their training suits their needs. For example, to improve strength do an exercise for 3 sets, 6 reps at 70%1RM. To improve muscular endurance/tone muscle do exercise for 3 sets, 15 reps at 40% 1RM. Youtube clip

Maximum Heart Rate (MHR) Maximum heart rate = 220 – age So for a 17 year old MHR = 220 – 17 = 203 To work at a moderate intensity, in their aerobic zone, their target heart rate should be 60-79% MHR. 60% MHR = 203 x 0.6 79% MHR = 203 x 0.79 = 122 bpm = 160 bpm The nearer to 160 bpm the harder the exercise intensity. This method doesn’t take into account fitness levels of the individual. Further info on use of Heart Rate from British Cycling

Karvonen Theory This method takes into account Resting Heart Rate (RHR), so it is specific to the fitness level of the individual. MHR is calculated in the same way as the previous method: 220-age Heart Rate Reserve (HRR) is calculated as: MHR – RHR 17 year old with RHR of 65: HRR = 203 – 65 = 138 Training heart rate is calculated as: (heart rate reserve x training percentage) + resting heart rate 17 year old training at 74% intensity would calculate target HR by: 65 + (0.74 x 138) = 167 bpm Youtube clip explaining maximum heart rate method and Karvonen method

TASK Calculate 68% target heart rate for a 23 year old with a resting heart rate of 58 beats per minute. MHR = 220-age = 197 Heart Rate Reserve (HRR) = MHR – RHR = 197 – 58 = 139 Training heart rate = RHR + (% x HRR) = 58 + (0.68 x 139) = 58 + 95 = 153 bpm

Borg Scale The Borg scale requires the individual to give a subjective rating of the difficulty of the training  Rate of Perceived Exertion The scale is numerical from 0 to 20 where: 0 is the equivalent to being asleep. 20 is maximum intensity which would cause collapse within 30 seconds. What are the pro’s and con’s of this method? This is easy and cheap to implement but it is an estimate and doesn’t give an accurate calculation

Percentage of functional threshold With this method an individual must work out the intensity at which they can work for one hour and then plan their training based on a percentage of that. British Cycling use of functional threshold

Technology Technology is always evolving and providing new methods to track training intensity and measure fitness levels. Pedometers Detects impact between foot and ground to count strides. HR monitors This is an old technology that previously involved wearing a strap around your torso and digital display on your wrist. Now they have developed into small watches that allow you to set target training zones, track calorie burn (based on age, weight, height, gender) and save data. GPS These monitors track your change in position and use the rate of change to calculate speed, acceleration, deceleration, and fatigue. Fitness based technology is advancing all the time – you are expected to have an up to date knowledge

An elite marathon runner is returning to the sport after a long-term injury. He intends to use heart rate (HR) as a means of measuring the intensity of his training. His current resting HR is 45 bpm and maximum HR is 196 bpm. (i) State Karvonen’s theory. (2) (ii) Using Karvonen’s theory, calculate the runner’s heart rate reserve. (1) (iii) Calculate the runner’s: lowest training heart rate (1) highest training heart rate (1)

(i) Maximum heart rate – resting heart rate = heart rate reserve (1) Heart rate reserve x %heart rate + resting heart rate = target heart rate (1) (ii) 151 bpm (196 – 45 = 151) (1) (iii) Lowest training heart rate 60% of 151 = 90.6 90.6 + 45 = 135.6 bpm (accept 136) (1) Highest training heart rate 80% of 151 = 120.8 120.8 +45 = 165.8 bpm (accept (166) (1)