Correlation of Anthropometry of Hand with Wrist Extensor Strength in Normal Asymptomatic Individuals

Introduction: Measurement of hand grip strength is the basic criteria for the evaluation of hand structure and function. The human hand serves various dynamic purposes in day to day activities of an individual. Infact, the entire upper limb is functional because of the hand. This study was carried out to find out if there is any relation between the anthropometric measurements of the hand and the wrist extensor strength of Indian adults. Methodology: A data was collected of 75 individuals with no pathological abnormalities from Acharya Vinoba Bhave Rural Hospital, Sawangi Meghe, Wardha. The consent of all the individuals was taken and they were informed about the procedure. The individuals were evaluated for wrist extensor strength by using a hand-held dynamometer. Also, the hand measurements such as hand length and width using a measuring tape. Results: The average wrist extensor strength of the right hand of the individuals was found to be more than that of the left hand. The length of both the hands was almost equal while the width of the left hand was greater than the right hand. Conclusion: There is a slight positive Correlation between the average wrist extensor strength and the length and width of the hand which can play a vital role in the rehabilitation process.

Modulatory Effect of Peripheral Magnetic and Neuromuscular Electrical Stimulation on Cortical Excitability: A Functional Near-Infrared Spectroscopy Study

Background: The present study was designed to investigate the effects of neuromuscular electrical stimulation (NMES) and peripheral magnetic stimulation (PMS) applied to the wrist extensor muscle on the cortical activity of healthy adults by using fNIRS. Methods: Fifteen healthy adult subjects (7 males, mean age: 27.13 ± 4.52 years) all received two different conditions of peripheral muscle stimulation in random order: (1) NMES and (2) PMS. The sessions were separated by at least 48 h as a washout period. During muscle stimulation, the motor evoked potential (MEP) of the left primary motor cortex (M1) was measured by transcranial magnetic stimulation (TMS) and the concentration of oxygenated (HbO) and deoxygenated (HbR) hemoglobin detected by fNIRS were used to evaluate the excitability and the activity of the cortex. Results: After the stimulation of the wrist extensor, the MEP amplitude in the left M1 area did not change in both conditions, and there was no difference between NMES and PMS condition. NMES reduced HbO values of several channels in the Prefrontal cortex (PFC), Somatosensory motor cortex (SMC) and Occipital cortex (OC), and HbR valus of several channels in the PFC and SMC. During the PMS stimulation period, the HbO value of all brain areas did not change significantly, while the HbR value of the SMC area decreased. The HbO and HbR value of the channels in the SMC did not differ between NMES and PMS. Inter-region of interest and inter-channel analysis between NMES and PMS showed no difference in functional connectivity. Conclusions: In the case of wrist extensor muscle stimulation, both NMES and PMS can induce cortical activation. PMS targeted to increases the activity of the contralateral SMC, while NMES increased contralateral SMC activity and negatively activated the PFC and OC.

Detection of effort maximality in adults performing isokinetic wrist flexion and extension

BACKGROUND: The difference between isokinetic eccentric to concentric strength ratios at high and low velocities (DEC) is a powerful tool for identifying submaximal effort in other muscle groups but its efficiency in terms of the wrist extensors (WE) and flexors (WF) isokinetic effort has hitherto not been studied. OBJECTIVE: The objective of the present study is to examine the usefulness of the DEC for identifying suboptimal wrist extensor and flexor isokinetic efforts. METHODS: Twenty healthy male volunteers aged 20–40 years (28.5 ± 3.2) were recruited. Participants were instructed to exert maximal and feigned efforts, using a range of motion of 20∘ in concentric (C) and eccentric (E) WE and WF modes at two velocities: 10 and 40∘/s. E/C ratios (E/CR) where then calculated and finally DEC by subtracting low velocity E/CR from high velocity ones. RESULTS: Feigned maximal effort DEC values were significantly higher than their maximal effort counterparts, both for WF and WE. For both actions, a DEC cutoff level to detect submaximal effort could be defined. The sensitivity of the DEC was 71.43% and 62.5% for WE ad WF respectively. The specificity was 100% in both cases. CONCLUSION: The DEC may be a valuable parameter for detecting feigned maximal WF and WE isokinetic effort in healthy adults.

Photobiomodulation Decreases Fatigue of the Wrist Extensors: Electromyographic and Dynamometric Analysis

This study analyzed the effects of photobiomodulation, on wrist extensor muscles when applied before a fatigue protocol. Twenty-eight men participated in a crossover, blinded, and controlled trial. Subjects performed grip dynamometry associated with superficial electromyography of the extensor carpi radialis, extensor carpi ulnaris, and flexor digitorum superficialis, which was used to evaluate muscle recruitment pattern by median frequency. The initial assessment was performed with a onerepetition maximum test. Twenty-four hours later the allocation was performed in two moments, and randomization was initially performed with 28 volunteers, divided between the two groups: control group, and the Low-Level Laser Therapy (30 mW, 0.06 cm2, 20 J/cm2, 1.2 J per point, and total energy of 10.8 J). Median frequency demonstrated Extensor Carpi Ulnaris fatigue in the control group as well as when compared after the fatigue protocol in the laser group. Exhaustion time was greater in the laser group and the fatigue protocol was effective at decreasing grip strength, with significant difference in the control group (p < 0.05). After the fatigue protocol, Low-Level Laser Therapy was effective in maintaining grip strength to increase exhaustion time and does not promote alterations in Median Frequency behavior at wrist extensor muscles.