Post by John A. Casler on Jul 9, 2009 10:30:25 GMT -8
This is from Jamie Carruthers as posted to SuperTraining
To visit SUPERTRAINING FORUM
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AGING AND RESISTANCE TRAINING INDUCED INCREASE IN MUSCLE SIZE
HULMI, J.J., SALMIJÄRVI, H., KATAJAVUORI, M., AHTIAINEN, J.P., HOLVIALA, J., SELÄNNE, H., KOVANEN, V., HÄKKINEN, K.,
MERO, A.A.
UNIVERSITY OF JYVÄSKYLÄ
14th annual Congress of the
EUROPEAN COLLEGE OF SPORT SCIENCE
Oslo/Norway, June 24-27, 2009
BOOK OF ABSTRACTS
Introduction: Resistance training (RT) increases muscle size but aging may (5) or may not (1) decrease this response. The present study
investigated muscle hypertrophy and gene expression adaptations to heavy RT in young and old healthy men.
Methods
Twenty-one previously untrained young men (26.0+-4.3 yrs) and 18 older men (61.2+-4.1) participated in a 21-week RT period, comprising
whole-body exercises twice a week. The training loads increased from 60 to 85% of 1RM, and the number of repetitions in each set
decreased from 15-20 to 5-6 during RT. Nineteen men (42.5+-20.0) served as controls (no RT). Vastus lateralis (VL) muscle fiber crosssectional
area (CSA), expression of muscle hypertrophy regulating genes (by Real-Time RT-PCR), and muscle force were analysed before
and after the 21-week period. Muscle biopsies were obtained 4-6 days after the last RT workout. Macronutrient intake was not controlled
but it was registered by 4-day diaries at weeks 0, 10.5 and 21.
Results: RT led to 1.2-1.4 -fold increases in strength of leg extensors and muscle fiber CSA (P<0.05). Concentric leg extension 1RM increased
similarly in young and old whereas isometric leg extension force increased more in young men (P<0.05). Type-I and mean (type
I+II) muscle fiber CSA increased two times more in young men (P<0.05). Young men habitually ingested 1.3-1.4 times more energy and
protein per body mass during RT than old men (P<0.05). Basal mRNA response to RT of activin receptor IIb, FLRG, MyoD, myogenin, p21,
cdk2 and MAFbx were not different between young and old. However, myostatin and myogenin mRNA increased in old compared to
young men (P<0.05).
Discussion: Larger muscle hypertrophy took place after RT in the young men. The present twice weekly heavy whole body RT may have
been too demanding for some previously untrained older individuals. This may have been associated with relatively lower energy and
protein intake observed in the old men. Protein and energy undernutrition among the elderly is common (3) and may be especially problematic
with RT that increases need for dietary protein (4). On the other hand, it is also possible that the adaptation capacity to RT simply
decreases with increasing age. It can be speculated that the increase in muscle myostatin gene expression in the old compared to the
young could be related to the observed smaller muscle hypertrophy in the old, as myostatin is a negative regulator of muscle size (2).
In conclusion, aging decreased the enlargement of muscle size during 21 weeks of training. This may be explained by smaller protein
and energy ingestion or by an increase in myostatin gene expression in the old.
References
1. Häkkinen K, et al. JGBSMS 53:B415-23, 1998
2. McPherron AC and Lee SJ. PNAS 94:12457-12461, 1997
3. Sullivan DH, et al. JAMA 281:2013-2019, 1999
4. Tarnopolsky MA, et al. JAP 73:1986-1995, 1992
5. Welle S, et al. JGBSMS 51:M270-5, 1996
To visit SUPERTRAINING FORUM
health.groups.yahoo.com/group/Supertraining/?yguid=44276758
AGING AND RESISTANCE TRAINING INDUCED INCREASE IN MUSCLE SIZE
HULMI, J.J., SALMIJÄRVI, H., KATAJAVUORI, M., AHTIAINEN, J.P., HOLVIALA, J., SELÄNNE, H., KOVANEN, V., HÄKKINEN, K.,
MERO, A.A.
UNIVERSITY OF JYVÄSKYLÄ
14th annual Congress of the
EUROPEAN COLLEGE OF SPORT SCIENCE
Oslo/Norway, June 24-27, 2009
BOOK OF ABSTRACTS
Introduction: Resistance training (RT) increases muscle size but aging may (5) or may not (1) decrease this response. The present study
investigated muscle hypertrophy and gene expression adaptations to heavy RT in young and old healthy men.
Methods
Twenty-one previously untrained young men (26.0+-4.3 yrs) and 18 older men (61.2+-4.1) participated in a 21-week RT period, comprising
whole-body exercises twice a week. The training loads increased from 60 to 85% of 1RM, and the number of repetitions in each set
decreased from 15-20 to 5-6 during RT. Nineteen men (42.5+-20.0) served as controls (no RT). Vastus lateralis (VL) muscle fiber crosssectional
area (CSA), expression of muscle hypertrophy regulating genes (by Real-Time RT-PCR), and muscle force were analysed before
and after the 21-week period. Muscle biopsies were obtained 4-6 days after the last RT workout. Macronutrient intake was not controlled
but it was registered by 4-day diaries at weeks 0, 10.5 and 21.
Results: RT led to 1.2-1.4 -fold increases in strength of leg extensors and muscle fiber CSA (P<0.05). Concentric leg extension 1RM increased
similarly in young and old whereas isometric leg extension force increased more in young men (P<0.05). Type-I and mean (type
I+II) muscle fiber CSA increased two times more in young men (P<0.05). Young men habitually ingested 1.3-1.4 times more energy and
protein per body mass during RT than old men (P<0.05). Basal mRNA response to RT of activin receptor IIb, FLRG, MyoD, myogenin, p21,
cdk2 and MAFbx were not different between young and old. However, myostatin and myogenin mRNA increased in old compared to
young men (P<0.05).
Discussion: Larger muscle hypertrophy took place after RT in the young men. The present twice weekly heavy whole body RT may have
been too demanding for some previously untrained older individuals. This may have been associated with relatively lower energy and
protein intake observed in the old men. Protein and energy undernutrition among the elderly is common (3) and may be especially problematic
with RT that increases need for dietary protein (4). On the other hand, it is also possible that the adaptation capacity to RT simply
decreases with increasing age. It can be speculated that the increase in muscle myostatin gene expression in the old compared to the
young could be related to the observed smaller muscle hypertrophy in the old, as myostatin is a negative regulator of muscle size (2).
In conclusion, aging decreased the enlargement of muscle size during 21 weeks of training. This may be explained by smaller protein
and energy ingestion or by an increase in myostatin gene expression in the old.
References
1. Häkkinen K, et al. JGBSMS 53:B415-23, 1998
2. McPherron AC and Lee SJ. PNAS 94:12457-12461, 1997
3. Sullivan DH, et al. JAMA 281:2013-2019, 1999
4. Tarnopolsky MA, et al. JAP 73:1986-1995, 1992
5. Welle S, et al. JGBSMS 51:M270-5, 1996