Browsing by Author "Sizer, Phillip S."
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Item Quality of life in chronic musculoskeletal symptomatic Chilean population: secondary analysis of National Health Survey 2009–2010(2020) Mena Iturriaga, María Jesús; Mauri Stecca, Manuel; Sizer, Phillip S.; Leppe, JaimeBackground: Health-related quality of life (HRQoL) is defined as the patient’s perception of their health status. HRQoL can be modified by illnesses, treatments or social and health policies. Chronic musculoskeletal pain is a modifying factor of HRQoL that leads to lower quality of life, elevated suffering and disability. Knowing HRQoL in subjects reporting chronic musculoskeletal symptoms (cMSS), like pain, discomfort or swollenness lasting more than 3 months, will provide information to health teams and organizations engaged in the Chilean health system. This study aim was to determine the relationship between HRQoL and musculoskeletal symptoms measured in three different Chilean groups: [1] without symptoms; [2] with acute symptoms; and [3] with cMSS. Methods: A secondary analysis of the 2009–10 Chilean National Health Survey (NHS) was executed to determine the relationship between HRQoL (measured with SF-12) in three MSS groups. The Chilean NHS considered a national, probabilistic, stratified and multistage sample of 5293 participants aged 15 and older; it was representative at the national, urban-rural and regional levels. A multivariate logistic regression model studied the relationship between cMSS and HRQoL, adjusted for age, sex, educational level and residence area as control variables (p < 0.05). Results: Out of 5293 participants in the NHS 2009–10, 5276 subjects were included for analysis. The median age was 46 years (IQR 31–60), 59.4% women, a median of 10 years formal education (IQR 7–12) and an urban residence in 85.2% of the population of the NHS 2009–10. The observed population prevalence of people with cMSS was 42.6% (95% CI 40.4–44.9). Presence of cMSS is a risk factor for low HRQoL, exhibited both in the physical (OR 3.1 95% CI 2.7–3.5) and mental (OR 1.9 95% CI 1.6–2,) HRQoL dimensions, independent of control variables. Conclusions: Physical and mental HRQoL are affected in people with cMSS, low educational level and advanced age. This is especially seen in women. This information will facilitate assessment and treatment of cMSS as a prevalent and multidimensional health problem.Publication The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat(2023) McCormick, Joseph B.; Drusch, Alexander S.; Lynch, Darragh J.; Seeber, Gesine H.; Wilford, Katherine F.; Hooper, Troy L.; Allen, Brad S.; O'Connell, Dennis G.; Mena-Iturriaga, Maria-Jesus; Kinyata J Cooper, Kinyata J.; Sizer, Phillip S.Background: Weightlifting is growing in popularity among recreational and competitive athletes. The barbell back squat (BackS) is commonly included in these training programs, while the barbell front squat (FrontS) is commonly performed as a component of other lifts such as the power clean or clean and jerk, it is less commonly practiced in isolation. Hypothesis/purpose: The purpose of this study was to examine the effects of VPAC performance on trunk muscle and LE biomechanical responses during loaded BackS versus FrontS in healthy subjects. Study design: Controlled Laboratory Study. Methods: Healthy male subjects with the ability to perform a sub-maximal loaded barbell squat lift were recruited. Subjects completed informed consent, demographic/medical history questionnaires and an instructional video. Subjects practiced VPAC and received feedback. Surface electromyography (sEMG) electrodes and kinematic markers were applied. Muscles included were the internal oblique (IO), external oblique (EO), rectus abdominis, iliocostalis lumborum (ICL), superficial multifidi, rectus femoris, vastus lateralis, biceps femoris, and gluteus maximus. Maximal voluntary isometric contractions established reference sEMG values. A squat one-rep-max (1RM) was predicted by researchers using a three to five repetition maximum (3RM, 5RM) load protocol. Subjects performed BackS trials at 75% 1RM while FrontS trials were performed at 75% BackS weight, both with and without VPAC. Subjects performed three repetitions of each condition with feet positioned on two adjacent force plates. Significant interactions and main effects were tested using a 2(VPAC strategy) x 2(squat variation) and 2(VPAC strategy) x 2(direction) within-subject repeated measures ANOVAs. Tukey's Post-Hoc tests identified the location of significant differences. Results: Trunk muscle activity was significantly higher during FrontS versus BackS regardless of VPAC condition. (IO: p=0.018, EO: p<0.001, ICL: p<0.001) VPAC increased performance time for both squat variations (p=.0011), which may be associated with decreased detrimental force potential on the lumbar spine and knees. VPAC led to improved ability to maintain a neutral lumbar spine during both squat variations. This finding is associated with decreased detrimental force potential on the lumbar spine. Conclusions: Findings could help guide practitioners and coaches to choose squat variations and incorporate VPAC strategies during their treatments and/or training programs.Publication The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat(2023) McCormick, Joseph B.; Drusch, Alexander S.; Lynch, Darragh J.; Seeber, Gesine H.; Wilford, Katherine F.; Hooper, Troy L.; Allen, Brad S.; O’Connell, Dennis G.; Mena-Iturriaga, Maria-Jesus; Cooper, Kinyata J.; Sizer, Phillip S.Background: Weightlifting is growing in popularity among recreational and competitive athletes. The barbell back squat (BackS) is commonly included in these training programs, while the barbell front squat (FrontS) is commonly performed as a component of other lifts such as the power clean or clean and jerk, it is less commonly practiced in isolation. Hypothesis/purpose: The purpose of this study was to examine the effects of VPAC performance on trunk muscle and LE biomechanical responses during loaded BackS versus FrontS in healthy subjects. Study design: Controlled Laboratory Study. Methods: Healthy male subjects with the ability to perform a sub-maximal loaded barbell squat lift were recruited. Subjects completed informed consent, demographic/medical history questionnaires and an instructional video. Subjects practiced VPAC and received feedback. Surface electromyography (sEMG) electrodes and kinematic markers were applied. Muscles included were the internal oblique (IO), external oblique (EO), rectus abdominis, iliocostalis lumborum (ICL), superficial multifidi, rectus femoris, vastus lateralis, biceps femoris, and gluteus maximus. Maximal voluntary isometric contractions established reference sEMG values. A squat one-rep-max (1RM) was predicted by researchers using a three to five repetition maximum (3RM, 5RM) load protocol. Subjects performed BackS trials at 75% 1RM while FrontS trials were performed at 75% BackS weight, both with and without VPAC. Subjects performed three repetitions of each condition with feet positioned on two adjacent force plates. Significant interactions and main effects were tested using a 2(VPAC strategy) x 2(squat variation) and 2(VPAC strategy) x 2(direction) within-subject repeated measures ANOVAs. Tukey's Post-Hoc tests identified the location of significant differences. Results: Trunk muscle activity was significantly higher during FrontS versus BackS regardless of VPAC condition. (IO: p=0.018, EO: p<0.001, ICL: p<0.001) VPAC increased performance time for both squat variations (p=.0011), which may be associated with decreased detrimental force potential on the lumbar spine and knees. VPAC led to improved ability to maintain a neutral lumbar spine during both squat variations. This finding is associated with decreased detrimental force potential on the lumbar spine. Conclusions: Findings could help guide practitioners and coaches to choose squat variations and incorporate VPAC strategies during their treatments and/or training programs.