vendex and Diabetic-Neuropathies

The purpose of this study was to investigate the effect of diabetes, motor nerve impairment, and training status on neuromuscular function by concurrent assessment of the torque-velocity relationship and muscle fiber conduction velocity (MFCV).. Four groups were studied (n = 12 each): sedentary patients with diabetes in the first (lower) and fourth (higher) quartile of motor nerve conduction velocity (D1 and D4, respectively), trained diabetic (TD) patients, and nondiabetic sedentary control (C) subjects. Maximal isometric and isokinetic contractions were assessed over a wide range of angular velocities for the elbow flexors and knee extensors to evaluate the torque-velocity relationship. Simultaneously, MFCV was estimated from surface electromyography of the vastus lateralis and biceps brachii.. Isometric strength was similar among groups. The dynamic strength of elbow flexors was reduced in patients with diabetes at the higher contraction speeds. The strength of knee extensors was lower in sedentary patients with diabetes at all velocities considered, with significantly lower values in D1 than that in D4 at 60°, 90°, and 120°·s(-1), whereas it was similar between TD and C subjects, especially at low contraction velocities. At the vastus lateralis, but not the biceps brachii, MFCV was lower in D1 and D4 as compared with TD and C subjects, showing similar values.. Muscle weakness in diabetes affects also the upper limb, although to a lower extent than the lower limb, is only partly related to motor nerve impairment, and is dependent on contraction velocity. Exercise training might counteract diabetes-induced alterations in muscle fiber contractile properties and MFCV.

Topics: Aged; Biomechanical Phenomena; Case-Control Studies; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Electromyography; Exercise Therapy; Humans; Male; Middle Aged; Motor Neurons; Muscle Contraction; Muscle Strength; Muscle, Skeletal; Neural Conduction; Single-Blind Method; Torque

The effect of a tendo-Achilles lengthening (TAL) procedure on ankle muscle performance has not been clearly established. The purpose of this study was to compare the effects of TAL and total-contact casting (TCC) with TCC alone on ankle muscle performance in subjects with diabetes mellitus (DM) and a neuropathic plantar ulcer.. Subjects were randomly assigned to either a TAL group (3 female and 12 male subjects) or a TCC group (4 female and 10 male subjects).. Muscle performance measurements were obtained using an isokinetic dynamometer.. Concentric plantar-flexor peak torque decreased 31% after TAL but returned to the baseline level after 8 months. Dorsiflexor peak torque did not change in either group. Plantar-flexor passive torque at 0 degrees of dorsiflexion decreased after TAL but increased to 60% of the baseline level after 8 months. Maximal dorsiflexion angle increased 11 degrees after TAL and remained increased at 8 months.. The TAL resulted in an increase in ankle dorsiflexion range of motion and a temporary reduction in concentric plantar-flexor peak torque and passive torque at 0 degrees of dorsiflexion. If TAL is being considered for people with DM and a neuropathic forefoot ulcer, the initial compromise in plantar-flexor muscle performance should be addressed.

Topics: Achilles Tendon; Analysis of Variance; Ankle Joint; Diabetic Foot; Diabetic Neuropathies; Female; Foot Ulcer; Humans; Male; Middle Aged; Muscle, Skeletal; Prospective Studies; Torque; Treatment Outcome

Patients with diabetes mellitus and peripheral neuropathy (DM and PN) often complain of joint stiffness. Although stiffness may contribute to some of the impairments and functional limitations found in these patients, it has not been quantified in this population. The purpose of this study was to quantify and compare passive ankle stiffness and dorsiflexion (DF) range of motion in subjects with DM and PN versus an age-matched comparison group.. Thirty-four subjects were tested (17 subjects with DM and PN and 17 subjects in an age-matched comparison group). There were 10 male subjects and 7 female subjects in each group.. A Kin-Com dynamometer was used to measure passive plantar flexor torque as each subject's ankle was moved from plantar flexion into dorsiflexion at 60(/s. The following variables were compared using a Student t test: initial angle (angle of onset of plantar flexor torque), maximal dorsiflexion angle, plantar flexor muscle excursion (difference between initial angle and maximal dorsiflexion angle), slope of the first half of the plantar flexor torque curve (stiffness 1 measurement), and slope of the second half of the plantar flexor torque curve (stiffness 2 measurement).. The subjects with DM and PN had smaller maximal dorsiflexion angles and less plantar flexor muscle excursion than the comparison group. There was no difference in initial angle, stiffness 1 measurement, or stiffness 2 measurement.. Although the subjects with DM and PN had less dorsiflexion range of motion than did the comparison group, there was no difference in stiffness between the groups. This finding suggests that people with DM and PN have "short" versus "stiff" plantar flexor muscles.

Topics: Adult; Aged; Ankle Joint; Diabetic Neuropathies; Elasticity; Electromyography; Female; Humans; Male; Middle Aged; Muscle Contraction; Observer Variation; Range of Motion, Articular; Stress, Mechanical; Torque

Portable, custom-made electronic dynamometry for the foot and ankle is a promising assessment method that enables foot and ankle muscle function to be established in healthy participants and those affected by chronic conditions. Diabetic peripheral neuropathy (DPN) can alter foot and ankle muscle function. This study assessed ankle toque in participants with diabetic peripheral neuropathy and healthy participants, with the aim of developing an algorithm for optimizing the precision of data processing and interpretation of the results and to define a reference frame for ankle torque measurement in both healthy participants and those affected by DPN. This paper discloses the software chain and the signal processing methods used for voltage-torque conversion, filtering, offset detection and the muscle effort type identification, which further allowed for a primary statistical report. The full description of the signal processing methods will make our research reproducible. The applied algorithm for signal processing is proposed as a reference frame for ankle torque assessment when using a custom-made electronic dynamometer. While evaluating multiple measurements, our algorithm permits for a more detailed parametrization of the ankle torque results in healthy participants and those affected by DPN.

Topics: Ankle; Ankle Joint; Diabetes Mellitus; Diabetic Neuropathies; Electronics; Humans; Muscle Strength; Muscle, Skeletal; Torque

Skeletal muscle strength is poorly described and understood in diabetic participants with diabetic peripheral neuropathy. This study aimed to investigate the extensor and flexor torque of the knee and ankle during concentric, eccentric, and isometric contractions in men with diabetes mellitus type 2 with and without diabetic peripheral neuropathy.. Three groups of adult men (n=92), similar in age, body mass index, and testosterone levels, were analyzed: 33 non-diabetic controls, 31 with type 2 diabetes mellitus, and 28 with diabetic peripheral neuropathy. The peak torques in the concentric, eccentric, and isometric contractions were evaluated using an isokinetic dynamometer during knee and ankle flexion and extension.. Individuals with diabetes and diabetic peripheral neuropathy presented similar low concentric and isometric knee and ankle torques that were also lower than the controls. However, the eccentric torque was similar among the groups, the contractions, and the joints.. Regardless of the presence of peripheral neuropathy, differences in skeletal muscle function were found. The muscle involvement does not follow the same pattern of sensorial losses, since there are no distal-to-proximal impairments. Both knee and ankle were affected, but the effect sizes of the concentric and isometric torques were found to be greater in the participants' knees than in their ankles. The eccentric function did not reveal differences between the healthy control group and the two diabetic groups, raising questions about the involvement of the passive muscle components.

Topics: Adult; Aged; Ankle; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Humans; Isometric Contraction; Knee; Lower Extremity; Male; Middle Aged; Muscle Strength; Muscle, Skeletal; Range of Motion, Articular; Torque

Diabetic patients have an altered gait strategy during walking and are known to be at high risk of falling, especially when diabetic peripheral neuropathy is present. This study investigated alterations to lower limb joint torques during walking and related these torques to maximum strength in an attempt to elucidate why diabetic patients are more likely to fall. 20 diabetic patients with moderate/severe peripheral neuropathy (DPN), 33 diabetic patients without peripheral neuropathy (DM), and 27 non-diabetic controls (Ctrl) underwent gait analysis using a motion analysis system and force plates to measure kinetic parameters. Lower limb peak joint torques and joint work done (energy expenditure) were calculated during walking. The ratio of peak joint torques and individual maximum joint strengths (measured on a dynamometer) was then calculated for 59 of the 80 participants to yield the ‘operating strength’ for those participants. During walking DM and DPN patients showed significantly reduced peak torques at the ankle and knee. Maximum joint strengths at the knee were significantly less in both DM and DPN groups than Ctrls, and for the DPN group at the ankle. Operating strengths were significantly higher at the ankle in the DPN group compared to the Ctrls. These findings show that diabetic patients walk with reduced lower limb joint torques; however due to a decrement in their maximum ability at the ankle and knee, their operating strengths are higher. This allows less reserve strength if responding to a perturbation in balance, potentially increasing their risk of falling.

Topics: Adult; Aged; Ankle Joint; Biomechanical Phenomena; Case-Control Studies; Diabetic Neuropathies; Gait; Humans; Knee Joint; Lower Extremity; Middle Aged; Muscle Strength; Torque; Walking

Descriptive study to compare relationships between muscle performance measures in 2 subject groups.. To determine the relationships between plantar flexor (PF) muscle stiffness, strength (concentric peak torque), and dorsiflexion (DF) range of motion (ROM) in subjects with diabetes who have peripheral neuropathy (n = 17, 10 men, 7 women; age = 58 +/- 11 years) and age-matched controls (n = 17, 10 men, 7 women; age = 62 +/- 6 years).. The relationships between muscle stiffness, strength, and joint ROM have not been clearly established. Furthermore, the effect of neuromuscular pathology on these relationships is unknown.. PF stiffness and strength measurements were obtained with an isokinetic dynamometer. DF ROM was measured with a goniometer. A Pearson correlation matrix was constructed for each subject group using stiffness, strength, and ROM variables. The percent contribution of passive torque to total torque was computed at 2 joint angles.. In subjects with diabetes and peripheral neuropathy (DM-PN) peak concentric PF torque was positively correlated with passive torque at 5 degrees DF (r = 0.77), Stiffness #1 (r = 0.58), and Stiffness #2 (r = 0.50). The percentage of passive PF torque at 5 degrees DF was greater in subjects with DM-PN, compared to control subjects (29.3 +/- 9.4% versus 12.6 +/- 5.9%).. The positive correlation between PF stiffness and strength, and the greater percentage of passive PF torque in subjects with DM-PN suggest that patients with decreased strength may use passive torque to maximize total torque. Therefore, treatment methods designed to decrease stiffness should be used cautiously.

Topics: Aged; Ankle Joint; Case-Control Studies; Confounding Factors, Epidemiologic; Diabetic Neuropathies; Female; Humans; Male; Middle Aged; Muscle Contraction; Range of Motion, Articular; Torque; Weight-Bearing

To determine the short-term muscular endurance and working capacity of leg muscles in long-term IDDM patients in relation to neuropathic complications, muscle strength, and metabolic control.. The muscular endurance of extensors and flexors at the ankle and knee was assessed in 44 IDDM patients and in 44 matched control subjects during 30 maximal isokinetic movements. The endurance index was the work performance of the last 5 movements relative to the first 5 movements. Total work was the summated work of all movements. All patients underwent a neurological evaluation, nerve conduction studies, and quantitative sensory tests.. The combined endurance index of the ankle extensors and flexors was 70% (51-88) (median [range]) in the diabetic group and 65% (55-82) in the control group (P < 0.01). For knee extensors and flexors the combined endurance index was 65% (55-103) for the diabetic patients and 63% (48-75) in the control subjects (P < 0.01). The endurance index related neither to the severity of neuropathy nor to the metabolic control (blood glucose and HbA1c) for any of the muscle groups. Diabetic patients had reduced strength of all muscle groups (14-24%, P < 0.02) and impaired total work performance (15-20%, P < 0.01) for ankle movements.. Long-term IDDM patients have increased endurance but reduced strength and work performance of leg muscles. The combined effect of the motor abnormalities is suggested to give rise to functional impairment, including an increased risk of falls and injuries.

Topics: Adult; Ankle Joint; Blood Glucose; Diabetes Mellitus, Type 1; Diabetic Neuropathies; Female; Glycated Hemoglobin; Humans; Knee Joint; Male; Middle Aged; Muscle Contraction; Muscle, Skeletal; Physical Endurance; Reference Values; Regression Analysis; Torque