Weight bearing exercise can elicit similar peak muscle activation as medium–high intensity resistance exercise in elderly women

The purpose of this study was to investigate the effects of how limb dominance and joint immobilization alter markers of physical demand and muscle activation during ambulation with axillary crutches. In a crossover, counterbalanced study design, physically active females completed ambulation trials with three conditions: (1) bipedal walking (BW), (2) axillary crutch ambulation with their dominant limb (DOM), and (3) axillary crutch ambulation with their nondominant limb (NDOM). During the axillary crutch ambulation conditions, the non-weight-bearing knee joint was immobilized at a 30-degree flexion angle with a postoperative knee stabilizer. For each trial/condition, participants ambulated at 0.6, 0.8, and 1.0 mph for five minutes at each speed. Heart rate (HR) and rate of perceived exertion (RPE) were monitored throughout. Surface electromyography (sEMG) was used to record muscle activation of the medial gastrocnemius (MG), soleus (SOL), and tibialis anterior (TA) unilaterally on the weight-bearing limb. Biceps brachii (BB) and triceps brachii (TB) sEMG were measured bilaterally. sEMG signals for each immobilization condition were normalized to corresponding values for BW.HR (p < 0.001) and RPE (p < 0.001) were significantly higher for both the DOM and NDOM conditions compared to BW but no differences existed between the DOM and NDOM conditions (p > 0.05). No differences in lower limb muscle activation were noted for any muscles between the DOM and NDOM conditions (p > 0.05). Regardless of condition, BB activation ipsilateral to the ambulating limb was significantly lower during 0.6 mph (p = 0.005) and 0.8 mph (p = 0.016) compared to the same speeds for BB on the contralateral side. Contralateral TB activation was significantly higher during 0.6 mph compared to 0.8 mph (p = 0.009) and 1.0 mph (p = 0.029) irrespective of condition. In conclusion, limb dominance appears to not alter lower limb muscle activation and walking intensity while using axillary crutches. However, upper limb muscle activation was asymmetrical during axillary crutch use and largely dependent on speed. These results suggest that functional asymmetry may exist in upper limbs but not lower limbs during assistive device supported ambulation.

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MRI Evaluation of Patella Alignment Before and After Anatomical Reconstruction of ACL Undergoing Unified Rehabilitation Programme Introduced by CMC Physical Therapy Team

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967114s00148 ◽

2014 ◽

Vol 2 (11_suppl3) ◽

pp. 2325967114S0014

Author(s):

Dariusz Straszewski ◽

Marcin Plenzler ◽

Joanna Szczepaniak ◽

Robert Śmigielski ◽

Beata Ciszkowska-Łysoń ◽

...

Keyword(s):

Patellar Tendon ◽

Muscle Activation ◽

Weight Bearing ◽

Tendon Graft ◽

Rehabilitation Programme ◽

Anatomical Reconstruction ◽

Patella Baja ◽

Functional Rehabilitation ◽

Patellar Tendon Graft ◽

The Impact

Objectives: The aim of the study was to asses the impact of the functional rehabilitation on patella alignment with MRI imaging in patients who underwent the ACL reconstruction. The surgical approach with the use of patellar tendon graft is known to carry the risk of lowering patella height (patella baja), which, in turn, may lead to accelerated cartilage wear in patellofemoral joint. Methods: 30 patients after the anatomical reconstruction of ACL took part in this study (23 male, and 7 female, mean age = 28 ± 10,6 years). During the procedure a patellar tendon graft was used. The Insali-Salvati ratio measured with MRI (images taken pre-procedural, and 9 months after the surgery) was used for the assessment of patellar alignment. The measurements were taken by one radiology specialist on MRI scans in sagittal view in PD sequence. During the examination, patellar joint was in flexion (approx.10 degrees). As the point of reference for patella’s position ISR ratio was in the range of 0.8 - 1.2. All patients were operated on by the same team of surgeons and underwent an unified rehabilitation programme led by a team of selected physiotherapists. The main features of the programme were: an early muscle activation (second day after the procedure); mobilisation of the patella and tissues of the anterior compartment of the knee; weight bearing co-contraction exercises, and the sensomotoric training of the entire kinetic chain of the lower limb. The data recorded was statistically analysed using the Wilcoxon signed-rank test in order to establish parameters’ changes within the study group.. Results: The mean ISR value before the procedure was 0.84 (± 0,1), whereas 9 months after the surgery it was 0.85 (± 0,1). The results’ analysis did not show any statistically significant changes between ISR values. Nine months after the procedure patella baja has not been observed in any of the evaluated patients. Conclusion: The functional rehabilitation programme designed by the CMC team had no negative impact on patella alignment, as no patella baja, which is a common complication after these kinds of surgeries, has been observed. The applied functional rehabilitation programme enabled patients to keep the proper patella alignment, similar to the alignment recorded before the surgery.

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Peak force and maximal shortening velocity of soleus fibers after non-weight-bearing and resistance exercise

Journal of Applied Physiology ◽

10.1152/jappl.1997.82.1.189 ◽

1997 ◽

Vol 82 (1) ◽

pp. 189-195 ◽

Cited By ~ 22

Author(s):

Jeffrey J. Widrick ◽

Robert H. Fitts

Keyword(s):

Resistance Exercise ◽

Elevated Level ◽

Fiber Diameter ◽

Weight Bearing ◽

Normal Weight ◽

Peak Force ◽

Type I ◽

Shortening Velocity ◽

Adult Rats ◽

Cross Sectional

Widrick, Jeffrey J., and Robert H. Fitts. Peak force and maximal shortening velocity of soleus fibers after non-weight-bearing and resistance exercise. J. Appl. Physiol. 82(1): 189–195, 1997.—This study examined the effectiveness of resistance exercise as a countermeasure to non-weight-bearing-induced alterations in the absolute peak force, normalized peak force (force/fiber cross-sectional area), peak stiffness, and maximal shortening velocity ( V o) of single permeabilized type I soleus muscle fibers. Adult rats were subjected to one of the following treatments: normal weight bearing (WB), non-weight bearing (NWB), or NWB with exercise treatments (NWB+Ex). The hindlimbs of the NWB and NWB+Ex rats were suspended for 14 days via tail harnesses. Four times each day, the NWB+Ex rats were removed from suspension and performed 10 climbs (∼15 cm each) up a steep grid with a 500-g mass (∼1.5 times body mass) attached to their tail harness. NWB was associated with significant reductions in type I fiber diameter, absolute force, normalized force, and stiffness. Exercise treatments during NWB attenuated the decline in fiber diameter and absolute force by almost 60% while maintaining normalized force and stiffness at WB levels. Type I fiber V oincreased by 33% with NWB and remained at this elevated level despite the exercise treatments. We conclude that in comparison to intermittent weight bearing only (J. J. Widrick, J. J. Bangart, M. Karhanek, and R. H. Fitts. J. Appl. Physiol. 80: 981–987, 1996), resistance exercise was more effective in attenuating alterations in type I soleus fiber absolute force, normalized force, and stiffness but was less effective in restoring type I fiber V oto WB levels.

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