Muskelförlust vid immobilisering

[King Grub]

Strax under 1 % av muskeln försvinner per dag.

Purpose

Musculoskeletal injuries necessitate periods of disuse (i.e. limb immobilization) during which rapid skeletal muscle atrophy occurs. The relative susceptibility of different muscles of the thigh to disuse atrophy remains uninvestigated. We assessed muscle disuse atrophy of individual thigh muscles throughout one week of unilateral knee immobilization.

Methods

Thirteen healthy, young (20.2±0.6 y) men underwent 7 days of unilateral leg immobilization via knee bracing. MRI scans were performed bilaterally prior to, and following 2 and 7 days of immobilization to determine the volume and anatomical cross-sectional area (aCSA) of the individual muscle groups of the upper legs.

Results

In contrast to the control leg, total thigh muscle volume had decreased by 1.7±0.3 (P<0.01) and 5.5±0.6% (P<0.001) in the immobilized leg after 2 and 7 days of disuse, respectively. Muscle loss was significantly greater in the M. quadriceps (day 2; 1.7±0.3 (P<0.05) and day 7; 6.7±0.6%) when compared with the M. hamstrings (day 2; 1.4±0.2% (P<0.01) and day 7; 3.5±0.3%) following 7 days of disuse (P<0.001). Individual muscles of the thigh exhibited different atrophy rates with the M. vastus lateralis aCSA showing the greater (2.6±0.4 and 7.2±0.8%), and the M. gracilis the lesser (1.1±0.7 and 2.3±1.0%) decline following 2 and 7 days of immobilization, respectively (P<0.01).

Conclusion

Thigh muscle disuse atrophy occurs rapidly and is already evident within 2 days of leg immobilization and progresses at a similar rate over the next 5 days (~0.8% muscle loss per day). M. quadriceps muscle shows more atrophy when compared with the M. hamstrings.

Temporal Muscle-Specific Disuse Atrophy during One Week of Leg Immobilization. Medicine & Science in Sports & Exercise: November 1, 2019.

[PureWhey]

Finns det studie(r) på hur mycket man tappar om man slutar styrketräna, men inte är rörelsehindrad/skadad/etc?

[Termy]

Hittar ju inte studien när jag googlar =/

[Termy]

Ursprungligen postat av PureWhey

Finns det studie(r) på hur mycket man tappar om man slutar styrketräna, men inte är rörelsehindrad/skadad/etc?

https://sci-fit.net/detraining-retraining/

[PureWhey]

Ursprungligen postat av Termy

https://sci-fit.net/detraining-retraining/

Snyggt, tack.

[King Grub]

Introduction:

Short-term muscle disuse has been reported to lower both post-absorptive and post-prandial myofibrillar protein synthesis rates. This study assessed the impact of disuse on daily myofibrillar protein synthesis rates following acute (2 days) and more prolonged (7 days) muscle disuse under free living conditions.

Methods:

Thirteen healthy young men (age, 20±1 y; BMI, 23±1 kg·m-2) underwent 7 days of unilateral leg immobilization via a knee brace with the non-immobilized leg acting as a control. Four days prior to immobilization participants ingested 400 mL 70% deuterated water, with 50 mL doses consumed daily thereafter. Upper leg bilateral MRI scans and muscle biopsies were collected before, and after 2 and 7 days of immobilization to determine quadriceps volume and daily myofibrillar protein synthesis rates.

Results:

Immobilization reduced quadriceps volume in the immobilized leg by 1.7±0.3 and 6.7±0.6 % after 2 and 7 days, respectively, with no changes in the control leg. Over the one week immobilization period myofibrillar protein synthesis rates were 36±4% lower in the immobilized (0.81±0.04%·d-1) compared with the control (1.26±0.04%·d-1) leg (P<0.001). Myofibrillar protein synthesis rates in the control leg did not change over time (P=0.775), but in the immobilized leg were numerically lower during the 0-2 day period (16±6%, 1.11±0.09%·d-1, P=0.153) and were significantly lower during the 2-7 day period (44±5%, 0.70±0.06%·d-1, P<0.001) when compared with the control leg.

Conclusion:

One week of muscle disuse induces a rapid and sustained decline in daily myofibrillar protein synthesis rates in healthy young men.

Short-term muscle disuse induces a rapid and sustained decline in daily myofibrillar protein synthesis rates. American Journal of Physiology-Endocrinology and Metabolism, 19 November 2019.