Knee extensor and plantar flexor muscle size and function following 90 days of bed rest with or without resistance exercise

2004 ◽  
Vol 93 (3) ◽  
pp. 294-305 ◽  
Author(s):  
Bj�rn A. Alkner ◽  
Per A. Tesch
Keyword(s):  
Resistance Exercise ◽  
Knee Extensor ◽  
Bed Rest ◽  
Muscle Size ◽  
Plantar Flexor ◽  
Flexor Muscle ◽  
And Function

Hypertrophy of chronically unloaded muscle subjected to resistance exercise

2004 ◽  
Vol 96 (4) ◽  
pp. 1451-1458 ◽  
Author(s):  
P. A. Tesch ◽  
J. T. Trieschmann ◽  
A. Ekberg
Keyword(s):  
Muscle Strength ◽  
Resistance Exercise ◽  
Lower Limb ◽  
Weight Bearing ◽  
Knee Extensor ◽  
Extensor Muscle ◽  
Muscle Volume ◽  
Electromyographic Activity ◽  
Plantar Flexor ◽  
Flexor Muscle

In an effort to simulate the compromised function and atrophy of lower limb muscles experienced by astronauts after spaceflight, 21 men and women age 30-56 yr were subjected to unilateral lower limb unloading for 5 wk. Whereas 10 of these subjects performed unilateral knee extensor resistance exercise (ULRE) two or three times weekly, 11 subjects (UL) refrained from training. The exercise regimen consisted of four sets of seven maximal actions, using an apparatus that offers concentric and eccentric resistance by utilizing the inertia of rotating flywheel(s). Knee extensor muscle strength was measured before and after UL and ULRE, and knee extensor and ankle plantar flexor muscle volumes were determined by means of magnetic resonance imaging. Surface electromyographic activity measured after UL inferred increased muscle use to perform a given motor task. UL induced an 8.8% decrease ( P < 0.05) in knee extensor muscle volume. After ULRE and as a result of only ∼16 min of maximal contractile activity over the 5-wk course, muscle volume increased 7.7% ( P < 0.05). Muscle strength decreased 24-32% ( P < 0.05) in response to UL. Group ULRE showed maintained ( P > 0.05) strength. Ankle plantar flexor muscle volume of the unloaded limb decreased ( P < 0.05) in both groups (UL 10.5%; ULRE 11.1%). In neither group did the right weight-bearing limb show any change ( P > 0.05) in muscle volume or strength. The results of this study provide evidence that resistance exercise not only may offset muscle atrophy but is in fact capable of promoting marked hypertrophy of chronically unloaded muscle.

Resistance exercise prevents plantar flexor deconditioning during bed rest

1997 ◽  
Vol 29 (11) ◽  
pp. 1462-1468 ◽  
Author(s):  
MARCAS M. BAMMAN ◽  
GARY R. HUNTER ◽  
BRUCE R. STEVENS ◽  
MARK E. GUILLIAMS ◽  
MICHAEL C. GREENISEN
Keyword(s):  
Resistance Exercise ◽  
Bed Rest ◽  
Plantar Flexor

Recovery of medial gastrocnemius muscle grafts in rats: implications for the plantar flexor group

1994 ◽  
Vol 77 (6) ◽  
pp. 2773-2777 ◽  
Author(s):  
S. W. Miller ◽  
C. A. Hassett ◽  
T. P. White ◽  
J. A. Faulkner
Keyword(s):  
Group Structure ◽  
Muscle Group ◽  
Medial Gastrocnemius ◽  
Maximum Force ◽  
Plantar Flexor ◽  
Flexor Muscle ◽  
And Function ◽  
Total Muscle ◽  
Medial Gastrocnemius Muscle ◽  
Degree Of Recovery

Medial gastrocnemius (MGN) muscles were grafted in 18 rats and evaluated at 60, 90, and 120 days after the operation. Our purpose was to investigate the degree of recovery of the vascularized MGN grafts and the entire plantar flexor muscle group. Compared with control values, muscle mass and maximum force of MGN grafts were decreased by 33 and 38% at 60 days, 22 and 32% at 90 days, and 13 and 15% at 120 days. At 60 and 90 days, the deficits in maximum force for the entire plantar flexor muscle group, including the graft, were 29 and 17%, respectively. No difference was observed at 120 days. At 60 days, the deficit in the total mass of the plantar flexor group was 14% compared with control values, but by 90 days no deficit was observed. The restoration of normal plantar flexor group structure and function indicates that the degree of recovery attained by MGN grafts, although not complete, was sufficient to ensure that the performance of the total muscle group was not compromised.

Mouse Plantar Flexor Muscle Size and Strength After Inactivity and Training

2010 ◽  
Vol 81 (7) ◽  
pp. 632-638
Author(s):  
Joseph C. Wenke ◽  
Gordon L. Warren ◽  
Christopher R. Rathbone ◽  
Robert B. Armstrong
Keyword(s):  
Muscle Size ◽  
Plantar Flexor ◽  
Flexor Muscle ◽  
And Training

scholarly journals Plantar flexor moment arm and muscle volume predict torque-generating capacity in young men

2014 ◽  
Vol 116 (5) ◽  
pp. 538-544 ◽  
Author(s):  
Josh R. Baxter ◽  
Stephen J. Piazza
Keyword(s):  
Plantar Flexion ◽  
Young Men ◽  
Knee Extensor ◽  
Muscle Volume ◽  
Joint Torque ◽  
Muscle Size ◽  
Plantar Flexor ◽  
Moment Arm ◽  
Joint Rotation ◽  
Moment Arms

Muscle volume is known to correlate with maximal joint torque in humans, but the role of muscle moment arm in determining maximal torque is less clear. Moderate correlations have been reported between maximal isometric knee extensor torque and knee extensor moment arm, but no such observations have been made for the ankle joint. It has been suggested that smaller muscle moment arms may enhance force generation at high rates of joint rotation, but this has not yet been observed for ankle muscles in vivo. The purpose of the present study was to correlate plantar flexor moment arm and plantar flexor muscle volume with maximal plantar flexor torque measured at different rates of plantar flexion. Magnetic resonance imaging was used to quantify the plantar flexor moment arm and muscle volume of the posterior compartment in 20 healthy young men. Maximal plantar flexor torque was measured isometrically and at three plantar flexion speeds using an isokinetic dynamometer. Plantar flexor torque was significantly correlated with muscle volume (0.222 < R2 < 0.322) and with muscle moment arm at each speed (0.323 < R2 < 0.494). While muscle volume was strongly correlated with body mass and stature, moment arm was not. The slope of the torque-moment arm regression line decreased as the rate of joint rotation increased, indicating that subjects with small moment arms experienced smaller reductions in torque at high speeds. The findings of this study suggest that plantar flexor moment arm is a determinant of joint strength that is at least as important as muscle size.

Changes in muscle size, architecture, and neural activation after 20 days of bed rest with and without resistance exercise

2001 ◽  
Vol 84 (1-2) ◽  
pp. 7-12 ◽  
Author(s):  
Yasuo Kawakami ◽  
Hiroshi Akima ◽  
Keitaro Kubo ◽  
Yoshiho Muraoka ◽  
Hiroshi Hasegawa ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Bed Rest ◽  
Muscle Size ◽  
Neural Activation

Influence of concurrent exercise or nutrition countermeasures on thigh and calf muscle size and function during 60 days of bed rest in women

2007 ◽  
Vol 191 (2) ◽  
pp. 147-159 ◽  
Author(s):  
T. A. Trappe ◽  
N. A. Burd ◽  
E. S. Louis ◽  
G. A. Lee ◽  
S. W. Trappe
Keyword(s):  
Bed Rest ◽  
Calf Muscle ◽  
Muscle Size ◽  
Concurrent Exercise ◽  
And Function

scholarly journals Association between plantar flexor muscle volume and dorsiflexion flexibility in healthy young males: ultrasonography and magnetic resonance imaging studies

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Tadashi Suga ◽  
Masafumi Terada ◽  
Keigo Tomoo ◽  
Yuto Miyake ◽  
Takahiro Tanaka ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Muscle Volume ◽  
Muscle Size ◽  
Plantar Flexor ◽  
Passive Stiffness ◽  
Resonance Imaging ◽  
Flexor Muscle ◽  
Joint Flexibility ◽  
Young Males

Abstract Background Although joint flexibility is important for human locomotion, the determinants of joint flexibility are not fully understood. In this study, we examined the relationship between dorsiflexion flexibility and plantar flexor muscle size in healthy young males. Methods and results The dorsiflexion flexibility was assessed using range of motion (ROM) and stiffness during active and passive dorsiflexion. Active ROM was defined as the maximal angle during voluntary dorsiflexion. Passive ROM was defined as the angle at the onset of pain during passive dorsiflexion. Passive stiffness was calculated as the slope of the linear portion of the torque-angle curve between 10º and 20º dorsiflexion of the ankle during passive dorsiflexion. In the first study, the plantar flexor muscle volume (MV) in 92 subjects was estimated on the basis of the lower leg length and plantar flexor muscle thickness, as measured using ultrasonography. The estimated plantar flexor MV correlated significantly with active ROM (r = -0.433), passive ROM (r = -0.299), and passive stiffness (r = 0.541) during dorsiflexion (P = 0.01 for all). In the second study, the plantar flexor MV in 38 subjects was measured using magnetic resonance imaging. The plantar flexor MV correlated significantly with plantar flexor active ROM (r = -0.484), passive ROM (r = -0.383), and passive stiffness (r = 0.592) during dorsiflexion (P = 0.05 for all). Conclusions These findings suggest that a larger plantar flexor MV is related to less dorsiflexion flexibility in healthy young males.

Aerobic exercise does not compromise muscle hypertrophy response to short-term resistance training

2013 ◽  
Vol 114 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Tommy R. Lundberg ◽  
Rodrigo Fernandez-Gonzalo ◽  
Thomas Gustafsson ◽  
Per A. Tesch
Keyword(s):  
Resistance Exercise ◽  
Muscle Hypertrophy ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Muscle Size ◽  
Mrna Levels ◽  
Cross Sectional ◽  
Before And After

This study tested the hypothesis that chronic aerobic and resistance exercise (AE+RE) would elicit greater muscle hypertrophy than resistance exercise only (RE). Ten men (25 ± 4 yr) performed 5 wk unilateral knee extensor AE+RE. The opposing limb was subjected to RE. AE completed 6 hr prior to RE consisted of ∼45 min one-legged cycle ergometry. RE comprised 4 × 7 maximal concentric-eccentric knee extensions. Various indexes of in vivo knee extensor function were measured before and after training. Magnetic resonance imaging (MRI) assessed m. quadricep femoris (QF) cross-sectional area (CSA), volume, and signal intensity (SI). Biopsies obtained from m. vastus lateralis determined fiber CSA, enzyme levels, and gene expression of myostatin, atrogin-1, MuRF-1, PGC-1α, and VEGF. Increases ( P < 0.05) in isometric strength and peak power, respectively, were comparable in AE+RE (9 and 29%) and RE (11 and 24%). AE+RE showed greater increase (14%; P < 0.05) in QF volume than RE (8%). Muscle fiber CSA increased 17% after AE+RE ( P < 0.05) and 9% after RE ( P > 0.05). QF SI increased (12%; P < 0.05) after AE+RE, but not RE. Neither AE+RE nor RE showed altered mRNA levels. Citrate synthase activity increased ( P < 0.05) after AE+RE. The results suggest that the increased aerobic capacity shown with AE+RE was accompanied by a more robust increase in muscle size compared with RE. Although this response was not carried over to greater improvement in muscle function, it remains that intense AE can be executed prior to RE without compromising performance outcome.

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