Fitness information
PART 1: PHYSIOLOGICAL DEMANDS OF PLAYERS DURING POLOCROSSE COMPETITION
By Cassie Trewin
Department of Physiology
Australian Institute of Sport
INTRODUCTION
The 1999 National Elite Junior Polocrosse Camp, held in April, provided the perfect opportunity for physiologists from the Australian Institute of Sport to get their hands on the top junior players and find out more about the sport. To date, there is little information available on the physiological demands placed on riders during Polocrosse competition.
Eight boys and four girls kindly donated their bodies to the physiology team and were monitored during two 8 minute chukkas of a Polocrosse game. All players wore Polar Heart Rate Monitors which recorded heart rate at 5sec intervals throughout both 8 minute chukkas. Blood lactate values were also recorded before and after each chukka. This involved a finger being pricked - to the dismay of some players! A small amount of pain endured by these players meant a lot of information gained, so we thank them kindly!
ENERGY PATHWAYS AND BLOOD LACTATE
Muscles are supplied with energy to perform exercise via two pathways. The aerobic pathway (with oxygen) is used for longer duration, lower intensity exercise. The anaerobic pathway (without oxygen) is used for short duration, high intensity exercise. A consequence of using the anaerobic pathway is that there is an accumulation of lactate in the blood stream (lactate is associated with the painful, fatigued feeling in muscles during exercise).
Aerobic and anaerobic pathways act simultaneously, although they have a different relative contribution to energy supplies depending on exercise intensity. With increased exercise intensity, the energy supply becomes more anaerobic and as a result, blood lactate increases. It has been shown that blood lactate is a useful indicator of exercise intensity. A blood lactate of around 4mM indicates moderate intensity exercise. This is the ‘threshold’ level above which exercise changes from being mainly aerobic to predominantly anaerobic.
For the chukkas analysed on camp, post-chukka lactates for all 12 players averaged 4.3mM. This indicates that the physiological demands of Polocrosse are of a moderate intensity and use a relatively even mix of both aerobic and anaerobic pathways. Some individuals produced blood lactates as high as 10mM, while others were as low as 2mM. This suggests that players who are directly involved in ball play (eg position 1 attempting a goal) can be working at a very high intensity (almost entirely anaerobic), while players who aren’t involved in ball play (eg position 1 watching the other team score a goal) may be working at a very low intensity (almost entirely aerobic).
HEART RATE
Heart rate is a common alternative to blood lactate for monitoring exercise intensity. It is cheaper and more practical than taking finger blood samples. (If you do not have access to a heart rate monitor, just place your finger on the side of your neck, count the number of beats in 15sec and multiply by 4). Normally, heart rate increases linearly with exercise intensity, which is often expressed as a percentage of maximum heart rate. Maximum heart rate can be estimated by 220 minus your age. For camp participants (with an average age of 16years) age predicted maximum heart rate was 204 beats per minute (bpm) (220-16). Exercising at 60-80% of maximum heart rate is considered moderate intensity (122-163bpm for camp participants).
The average heart rate for all chukkas played was 160bpm. This again indicated overall moderate intensity exercise demands for Polocrosse players. There were large fluctuations in heart rate throughout the chukkas (of up to 80bpm), possibly due to the intermittent nature of Polocrosse. Heart rates rose rapidly and remained elevated (at 170-200bpm and above) for around 1 minute while the ball was in play. Once a goal was scored all players would walk their horses back to centre field, which was reflected by a drop in heart rate to around 120-140bpm.
Extremely high peak heart rates were found in some players, indicating that sections of fast play can be quite physically demanding. Two thirds of the group had peaks over 200bpm and one third had peaks greater than their age predicted maximum (204bpm). It is likely that part of the high heart rates achieved during Polocrosse can be attributed to the adrenaline rush from riding a horse at a fast pace and to the nerves/anxiety from playing in a competition.
CONCLUSION
The physiological demands of Polocrosse are of a similar nature to other team sports (eg. soccer and hockey). Overall, the game is played at a moderate intensity, with a number of intermittent high intensity efforts. Fitness of the rider may be just as important as fitness of the horse. Players are required to execute skilled movements at the same time as controlling their horse and making quick tactical decisions about the next play. A fit rider will have no problems doing this, however, an unfit rider may find that fatigue interferes with their ability to execute skills or make good decisions near the end of a game. In a close game, this could mean the difference between winning and losing. Therefore, anyone with aspirations to be an elite Polocrosse player need to get out there and get fit!
December 1999
Last updated
September, 2005