These results quantify the contributions of individual neck muscles to moment-generating capacity and demonstrate that variations in force-generating capacity and moment arm throughout the range of motion can alter muscle moment-generating capacities.

Study Design. Three-dimensional moments were measured experimentally during maximum voluntary contractions of neck muscles in humans.Objectives. To characterize the maximum moments with attention paid to subject size and gender, to calculate moments at different locations in the neck, and to quantify the relative magnitudes of extension, flexion, lateral bending, and axial rotation moments.Summary of Background Data. Few studies of neck strength have measured moments in directions other than extension, and it is difficult to compare results among studies because moments often are resolved at different locations in the cervical spine. Further, it is not clear how subject size, gender, and neck geometry relate to variations in the moment-generating capacity of neck muscles.Methods. Maximum moments were measured in 11 men and 5 women with an average age of 31 years (range, 20 -42 years). Anatomic landmarks were digitized to resolve moments at different locations in the cervical spine.Results. When moments were resolved about axes through the midpoint of the line between the C7 spinous process and the sternal notch, the maximum moments were as follows: extension (men, 52 Ϯ 11 Nm; women, 21 Ϯ 12 Nm), flexion (men, 30 Ϯ 5 Nm; women, 15 Ϯ 4 Nm), lateral bending (men, 36 Ϯ 8 Nm; women, 16 Ϯ 8 Nm), and axial rotation (men 15 Ϯ 4; women, 6 Ϯ 3) Nm). The magnitudes of extension, flexion, and lateral bending moments decreased linearly with vertical distance from the lower cervical spine to the mastoid process.Conclusions. Moments in three dimensions were quantified with regard to subject size and location along the cervical spine. These data are needed to characterize neck strength for biomechanical analysis of normal and pathologic conditions.

Background The inactivated Sinopharm/BBIBP COVID‐19 vaccine has been widely used in the world and has joined the COVAX vaccine supply program for developing countries. It is also well adapted for usage in low‐ and middle‐income nations due to their low storage requirements. Objective This study aims to report on the kinetics, durability, and neutralizing ability of the induced immunity of the BBIBP vaccine, and the intensified antibody response elicited by the booster. Methods A total of 353 healthy adult participants, aged 20–74 years, were recruited in this multicenter study. A standard dose of the BBIBP vaccine was administered (Month 0), followed by a second standard dose (Month 1), and a booster dose (after Month 7). Vaccine‐induced virus‐specific antibody levels (SARS‐CoV‐2‐IgA/IgM/IgG), conventional virus neutralization test (cVNT), pseudovirus neutralization test (pVNT), and surrogate virus neutralization test (sVNT) were monitored over multiple time points. Results Neutralizing titers induced by the two doses of inactivated vaccine for COVID‐19 peaked at Month 2 and declined to 33.89% at Month 6. Following the booster dose, elevated levels of antibodies were induced for IgA, IgG, and neutralizing antibodies, with neutralizing titer reaching 13.2 times that of before the booster. Conclusion By monitoring the antibody titer levels postvaccination, this study has shown that serum antibody levels will decrease over time, but a notable spike in antibody levels postbooster highlights the anamnestic immune response. This signifies that the protection capability has increased following the injection of booster immunization.

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