Sunday, July 11, 2010

Masters athlete: Physiology & their performance

0 comments Posted by sinyen at 4:53 PM

(Image adapted from: Mckee.J , 2009)
Veterans are often recognize as people that are weaker, slower, less healthy compared to younger ones. However, there are Veterans athletes that still active in sports , still in quest for optimum performance and breaking world records. How is this achieved? What are the physiological obstacle that they have to overcome?

Master athletes are sportsmen or sports women that are involve in sport like track and field, road runningand cross country running. The age range for this group of athletes are 35 years old and above. Despite of the age limit, these veteran athletes are still on the quest for optimum performance in their sports career. However, aging is still an important factor that decreases their performance. In endurance exercise, the peak performance can be maintained around until year of 35 for an athlete, follow by modest decrease by the age of 50 -60 years old then later years, the performance decline the most. Compare to Resistance training that involves “sprint” events; the reduction in peak exercise performance with age tends to be greater in endurance training. The reasons are that both training involves different energy producing pathways to sustain muscle activity. This article would discuss about the physiological factors that affects the performance of master athletes.

Cardio respiration endurance and aerobic fitness
A progressive reduction in maximal oxygen consumption (Vo2max) / an individual’s maximal aerobic capacity appears to be the primary mechanism associated with declines in endurance performance with age. Vo2max is defined as the highest rate of oxygen consumption attainable during maximal or exhaustive exercise. As exercise intensity increases so does oxygen consumption. However, a point is reached where exercise intensity can continue to increases without the associated rise in oxygen consumption. Vo2max decreases with age. Maximum heart rate declines about one beat per year with age. Vo2max declines by about 5ml/kg per minute per decade beginning at age 25, with an accelerated decline after age of 65. This decline in maximal aerobic power is like adding 30 seconds to a 10k personal best each year. (Sports fitness advisor, n.d.) However, this deterioration is not necessarily due to the aging process. In some cases the decrease maybe is purely a reflection of increased body weight with no change in absolute values for ventilation of oxygen. It is thought that some of this decline may be associated to a progressive decrease in physical activity, whether it be total volume or intensity of training. With regular exercise, the decline may be as much as half the rate in master athletes as compared with non-athletes. Usually, decreases in maximal stroke volume, heart rate and arteriole-venous oxygen difference all appear to contribute to the age-related reductions in Vo2max in endurance-trained athletes.

Changes in Muscle Strength
Lost in muscle strength is another factor that causes the decline in performance of masters athletes. Sacropenia, lost of lean muscle mass is greater than the lost of endurance capacity in sprinters. Aged sprinters have shorter stride length, therefore require number if strides to cover the same distance. In aged athletes, there is also a decline in muscle cross sectional area, causing less effective muscle functioning. Low muscle mass also one of the reason elders would experience disability, balance abnormalities. The decreased number of motor neurons is also another contributing factor. Furthermore, High fat infiltration into muscle was associated with adverse effect such as poor knee extensor strength, muscle contractibility, muscle fiber requirement, and also muscle metabolism. All these eventually decrease or lower the performance of aged athletes. Loss of muscle mass is mostly caused by the decrease in the size of fast twitch muscle fibers; Individual fibers shrink approximately 30% between the age of 20 and 80 years.(Wright and Perricelli, 2007) Fast twitch muscle is used for maintenance of slow twitch muscle cell that is able to remain constant or expand with physical activity. However, resistance training able to reduce the shrinkage of type II muscle fibers and increase the blood supplies to the muscle fiber.

As the muscle mass of athlete reduced upon ageing process, the limits of performance also decline. The maximum power falls by 30% between 40 and 70 in both endurance (aerobic) and sprint (anaerobic) events. The performance also inhibited by the limiting factor of the VO2 max level, result from the reduced capacity of heart and the difference in O2 solution level between arterial and venous blood performance.
performance of master athletes
(Graph adapted from: High-Tech Training ,n.d)


Aging Heart and Performance
The heart capacity to pump blood and deliver oxygen in veteran athlete is another factor that limits their sport performance. By the age of 60 the average heart rate is around 160 beats per minute compare to 220 beats per minutes. Heart rate increases linearly with exercise intensity and oxygen consumption thus, affecting the lactate threshold and the VO2 max of the athlete. (Seiler.S. 2005.) The maximal heart rate determines the range of the athlete’s training zone. Training within this zone develops endurance and aerobic capacity.On the other hand, generally with increasing age, master athlete will have high risk of develop atherosclerosis, hardening of the arteries. Stiff arteries cannot open up or dilate adequately when challenged to do so to satisfy increased oxygen needs. Swedish researchers compared 9 master athletes with an average age of 75 to 11 sedentary but healthy controls. The athletes were found to have more flexible, less stiff arteries than the non-athletes. A study found that the athletes had more flexible arteries and, moreover, that flexibility was found in arteries in untrained muscle groups as well as trained ones.

Aging and Bones
Bone mass decreased as we age. Bone fractures easily occurred in veteran athlete as their bones contain less calcium, where their bones become porous. Thus, increases the risk of bone fractures and injuries. This causes their performance to decline and less susceptible to recovery of injured bones. To maintain optimal bone health, nutritional aspect plays an important role. For example, adequate energy balances by consuming enough calories to meet training demand. Calcium is the major component of bone mineral, adequate intake of calcium helps proper bone maintenance and recovery in Master athletes.

Lactate threshold
The lactate threshold (LT) or the Lactate Inflection Point is the exercise intensity at which lactic acid starts to accumulate in the blood stream during training and endurance sports. The LT is between 90% and 95% of maximum heart rate. The lactic acid starts to accumulate when the ATP is hydrolyzed in the muscle, releasing hydrogen ions that are transported out to the blood. This happens when the lactate is produce faster than it is removed. In sport physiology, the LT is use to measure the ability of sportsmen to sustain a high fraction of one’s maximal oxygen consumption during sub maximal exercise. A research shows that a reduction in LT appears to be the causes of the decline in endurance performance among young adult to early middle age. However, the LT does not appear to change with age when expressed as the percentage of VO2 max, it is thus plausible that the contribution of LT to the age related reduction on endurance performance is mediated, by the reduction in VO2 max. (Tanaka, Seals. 2003).

Physiological Change and Training.

Physiological Change

How to offset this change

Loss of skeletal muscle mass

-Start engaging in resistance exercise (i.e., weights) 2-3 times per week

Decline in VO2 MAX

-Boost training, making sure to include high-intensity running.

Loss of bone mass

-Weight-bearing exercise

-Achieve energy balance

-Consume 1,000-1,200 mg calcium/day

-Hormone replacement in postmenopausal women

Decreased metabolism

-Maintain lean mass with high level of training

-Attain energy balance

-Eat small, frequent meals

Menopause (women athlete)

-Hormone Replacement

-Increased calcium intake up to 1,500 mg/day


Photobucket

(Figure adapted from: Tanaka. H, Seals D.R 2003)

References:

1.Doherty, T.J. 2003. Invited Review: Aging and Sarcopenia. J.Appl Physiol 95:1717-1727,2003.

2.Ransdell,L.B., Vener,J., and Huberty,J., 2009. Masters Athletes:An Analysis of Running, Swinning and Cycling Performance by Age and Gender. J Exerx Sci Fit. Vol 7. No 2(suppl). S61-S73.

3. Rittweger,J , Kwiet, A. Felsenberg,D. 2004. Physical Performance in Aging Elite Athletes- Challenging the Limits of Physiology. J Musculoskel Neuron Interact 4(2):159-160.

4.Rittweger,J.,Maffulli,N., and Narici,M.V., 2008. Sprint and Endurance Power and Ageing: An Analysis of Master Athletic World Records. Proc. R. Soc. B 2008 276, 683-689.

5. Tanaka, H, Seals D.R. 2008. Endurance Exercise Performance in Masters Athletes: Age-Associated Changes and Underlying Physiological Mechanism. J Appl Physiol 5886.1 pp 55-63.

6. Tanaka, H, Seals D.R. 2003. Physiology of Aging Invited Reviews: Dynamic exercise performance in Masters Athletes: insight into the effects of primary human aging on physiological functional capacity. J Appl Physiol 95:2152-2162, 2003.

7. Tulle,E. 2008. Acting your age? Sports Science and the Aging Body. Journal of Aging Studies 22(2008) 340-347.

8. Wright, V.J and Perricelli,B.C. 2007 Age – Related Rates of Decline in Performance Among Elite Senior Athletes. The American Journal of Sports Medicine, Vol. X, No.X DOI : 10.1177/0363546507309673.

9.Anderson,O., n.d., VO2 Max: Can Veteran athletes prevent a decline in aerobic capacity? [Online]. Available from: < http://www.pponline.co.uk/encyc/0697.htm > [Accessed on 10 th July 2010 ]

10.Kimberl,J., Mueller-Brown, MS,BD, n.d, Maintaining Peak Endurance Performance After 40. [Online]. Available from :< http://www.scribd.com/doc/14442692/The-Older-Athlete > [Accessed on 10 th July 2010 ]

11.Hendler, B., 2010. What Does Every Masters Athlete Have in Common? [Online]. Available from: < http://www.athleticamps.com/cycling/coaching/id0075/ > [Accessed on 10 th July 2010]

12.Seiler.S. 2005. Exercise Physiology. [Online]. Available from:< http://home.nia.no/~stephens.exphys.html > [Accessed 3rd July 2010]

13.Schwirian, C. What is Exercise Physiology? [Online]. Available from:http://www.biosci.ohiou.edu/Faculty/schwirian/Athlete%20&%20Coaches%20page/VO2max%20summary%20resultsa%20Runners.htm > [Accessed on 10th July 2010]

14.Sports fitness advisor, n.d., A guide to Vo2 max. [Online]. Available from:http://www.sport-fitness-advisor.com/VO2%20max > [Accessed on 10 th July 2010 ]

15. Wilmore,J.H., Costill, D.L .1999. The Physiology of aging as it relates to sports. [Online]. Available from: http://www.thefreelibrary,com/The+physiology+of+aging+as+it+relates+to+sports.(Excerpt)-a0122264591 > [Accessed 10th July 2010]




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