Post by carruthersjam on May 26, 2008 10:07:56 GMT -8
Explosive heavy-resistance training in old and very old adults:
changes in rapid muscle force, strength and power.
Scand J Med Sci Sports. 2008 Jan 30.
Caserotti P, Aagaard P, Buttrup Larsen J, Puggaard L.
Age-related decline in muscle power predicts falls, motor impairments
and disability. Recent guidelines suggested that training programs
should be tailored to maximize muscle power. This study investigated
the effects of 12 weeks of explosive-type heavy-resistance training
(75-80% of 1 repetition maximum) in old (60-65 years, TG60) and very
old (80-89 years, TG80) community-dwelling women. Training was
performed with maximal intentional acceleration of the training load
during the concentric movement phase.
Maximal isometric voluntary muscle strength (MVC), rapid force
capacity, assessed as rate of force development (RFD), and impulse,
maximal muscle power during a countermovement jump (CMJ) and during
unilateral leg extension task (LEP) were evaluated. RFD, impulse and
MVC increased by 51%, 42% and 28% in TG80, and by 21%, 18% and 18% in
TG60, respectively. CMJ jump height increased by 18% and 10% in TG80
and TG60, respectively, while jump peak power increased in TG60 (5%).
Finally, LEP increased 28% in TG80 and 12% in TG60.
These findings demonstrate that explosive-type heavy-resistance
training seems to be safe and well tolerated in healthy women even in
the eighth decade of life and elicits adaptive neuromuscular changes
in selected physiological variables that are commonly associated with
the risk of falls and disability in aged individuals.
==========================
Changes in power and force generation during coupled eccentric-
concentric versus concentric muscle contraction with training and
aging.
Eur J Appl Physiol. 2008 May;103(2):151-61.
Caserotti P, Aagaard P, Puggaard L.
Age-related decline in maximal concentric muscle power is associated
with frailty and functional impairments in the elderly. Compared to
concentric contraction, mechanical muscle output is generally
enhanced when muscles are rapidly pre-stretched (eccentric
contraction), albeit less pronounced with increasing age.
Exercise has been recommended to prevent loss of muscle power and
function and recent guidelines indicate training program for
increasing muscle power highly relevant for elderly subjects. This
study examined the differences in muscle power, force and movement
pattern during concentric-alone and coupled eccentric-concentric
contraction and selected functional motor performances before and
after 36-week multicomponent training including aerobic, strength,
balance, flexibility and coordination components in elderly males.
Vertical force, excursion, velocity, power and acceleration of the
body center of mass were measured in two standardised vertical jumps
(squatting jump, SQJ; countermovement jump, CMJ). Pre-stretch
enhancement during CMJ did not improve performance [i.e., no enhanced
maximal muscle power (P (peak)) and jump height (JH)] compared to
concentric-alone muscle contraction (SQJ).
Nevertheless, pre-stretch enhancement occurred as for similar SQJ and
CMJ maximal performance, elderly people employed lower mechanical
work, higher mean muscle power (P (mean)), shorter concentric phase
duration and shorter body center of mass displacement during CMJ.
Post training, CMJ P(peak), P (mean) and JH increased in training
group (P < 0.05) while P (peak) and JH decreased in control group
during the CMJ and SQJ (P < 0.05). In conclusion, long-term training
counteracted the age-related decline in muscle power and functional
performance observed in the control subjects, while substantial gains
in muscular performance were observed in the trained elderly.
==========================
Mechanical muscle function, morphology, and fiber type in lifelong
trained elderly.
Med Sci Sports Exerc. 2007 Nov;39(11):1989-96.
Aagaard P, Magnusson PS, Larsson B, Kjaer M, Krustrup P.
PURPOSE: Maximal muscle contraction force and muscle mass are both
reduced during the natural aging process. Long-term training may be
used to attenuate this age-related loss in muscle function and muscle
size. METHODS: Maximum isometric quadriceps strength (MVC), rate of
force development (RFD), and muscle fiber composition and size (CSA)
were studied in elderly individuals (68-78 yr) chronically exposed (>
50 yr) to either endurance (E) or strength (S) training, and in age-
matched, untrained (U) elderly group. RESULTS: E and S showed greater
MVC than did U. Contractile RFD was elevated in S compared with U,
and S also demonstrated greater type II fiber CSA than did U and E.
The proportion of type I fibers was greater in E compared with U and
S.
CONCLUSIONS: Muscle fiber size and mechanical muscle performance,
particularly RFD, were consistently elevated in aged individuals
exposed to chronic (i.e., lifelong) strength training. This relative
preservation in muscle morphology and function may provide an
important physical reserve capacity to retain muscle mass and
function above the critical threshold for independent living at old
age.
changes in rapid muscle force, strength and power.
Scand J Med Sci Sports. 2008 Jan 30.
Caserotti P, Aagaard P, Buttrup Larsen J, Puggaard L.
Age-related decline in muscle power predicts falls, motor impairments
and disability. Recent guidelines suggested that training programs
should be tailored to maximize muscle power. This study investigated
the effects of 12 weeks of explosive-type heavy-resistance training
(75-80% of 1 repetition maximum) in old (60-65 years, TG60) and very
old (80-89 years, TG80) community-dwelling women. Training was
performed with maximal intentional acceleration of the training load
during the concentric movement phase.
Maximal isometric voluntary muscle strength (MVC), rapid force
capacity, assessed as rate of force development (RFD), and impulse,
maximal muscle power during a countermovement jump (CMJ) and during
unilateral leg extension task (LEP) were evaluated. RFD, impulse and
MVC increased by 51%, 42% and 28% in TG80, and by 21%, 18% and 18% in
TG60, respectively. CMJ jump height increased by 18% and 10% in TG80
and TG60, respectively, while jump peak power increased in TG60 (5%).
Finally, LEP increased 28% in TG80 and 12% in TG60.
These findings demonstrate that explosive-type heavy-resistance
training seems to be safe and well tolerated in healthy women even in
the eighth decade of life and elicits adaptive neuromuscular changes
in selected physiological variables that are commonly associated with
the risk of falls and disability in aged individuals.
==========================
Changes in power and force generation during coupled eccentric-
concentric versus concentric muscle contraction with training and
aging.
Eur J Appl Physiol. 2008 May;103(2):151-61.
Caserotti P, Aagaard P, Puggaard L.
Age-related decline in maximal concentric muscle power is associated
with frailty and functional impairments in the elderly. Compared to
concentric contraction, mechanical muscle output is generally
enhanced when muscles are rapidly pre-stretched (eccentric
contraction), albeit less pronounced with increasing age.
Exercise has been recommended to prevent loss of muscle power and
function and recent guidelines indicate training program for
increasing muscle power highly relevant for elderly subjects. This
study examined the differences in muscle power, force and movement
pattern during concentric-alone and coupled eccentric-concentric
contraction and selected functional motor performances before and
after 36-week multicomponent training including aerobic, strength,
balance, flexibility and coordination components in elderly males.
Vertical force, excursion, velocity, power and acceleration of the
body center of mass were measured in two standardised vertical jumps
(squatting jump, SQJ; countermovement jump, CMJ). Pre-stretch
enhancement during CMJ did not improve performance [i.e., no enhanced
maximal muscle power (P (peak)) and jump height (JH)] compared to
concentric-alone muscle contraction (SQJ).
Nevertheless, pre-stretch enhancement occurred as for similar SQJ and
CMJ maximal performance, elderly people employed lower mechanical
work, higher mean muscle power (P (mean)), shorter concentric phase
duration and shorter body center of mass displacement during CMJ.
Post training, CMJ P(peak), P (mean) and JH increased in training
group (P < 0.05) while P (peak) and JH decreased in control group
during the CMJ and SQJ (P < 0.05). In conclusion, long-term training
counteracted the age-related decline in muscle power and functional
performance observed in the control subjects, while substantial gains
in muscular performance were observed in the trained elderly.
==========================
Mechanical muscle function, morphology, and fiber type in lifelong
trained elderly.
Med Sci Sports Exerc. 2007 Nov;39(11):1989-96.
Aagaard P, Magnusson PS, Larsson B, Kjaer M, Krustrup P.
PURPOSE: Maximal muscle contraction force and muscle mass are both
reduced during the natural aging process. Long-term training may be
used to attenuate this age-related loss in muscle function and muscle
size. METHODS: Maximum isometric quadriceps strength (MVC), rate of
force development (RFD), and muscle fiber composition and size (CSA)
were studied in elderly individuals (68-78 yr) chronically exposed (>
50 yr) to either endurance (E) or strength (S) training, and in age-
matched, untrained (U) elderly group. RESULTS: E and S showed greater
MVC than did U. Contractile RFD was elevated in S compared with U,
and S also demonstrated greater type II fiber CSA than did U and E.
The proportion of type I fibers was greater in E compared with U and
S.
CONCLUSIONS: Muscle fiber size and mechanical muscle performance,
particularly RFD, were consistently elevated in aged individuals
exposed to chronic (i.e., lifelong) strength training. This relative
preservation in muscle morphology and function may provide an
important physical reserve capacity to retain muscle mass and
function above the critical threshold for independent living at old
age.
