Comparison of Trunk Muscle Activity During Bridging Exercises Using a Sling in Patients with Low Back Pain

The aims of this study were to compare the activation of global and local muscles of the trunk during bridging with sling exercise (BSE), bridging with ball exercise (BBE), and normal bridging exercise (NBE) and to conduct and analyze these exercises in supine and prone positions to prove the effectiveness of sling exercises. Thirty patients with current low back pain (LBP) were recruited. In the supine and prone bridging exercise, each subject lifted their pelvis with their legs and feet in contact with the sling, ball, or normal surface. The electrical activities of the inferior oblique (IO), rectus abdominis (RA), multifidus (MF), and erector spinae (ES) muscles during the bridging exercises on the 3 surfaces were measured using surface electromyography (sEMG). For normalization, maximum sEMG signals were evaluated during each maximum voluntary isometric contraction (MVIC) maneuver. The root mean square during the exercise was normalized as a percentage of the MVIC (%MVIC). In the supine and prone positions, %MVIC of the IO, RA, MF, and ES during BSE was significantly higher than those during BBE and NBE (p < 0.05). In the supine position, %MVIC of the RA and ES during BBE was significantly higher than that during NBE (p < 0.05). In the prone position, all %MVIC during BBE were significantly higher than NBE (p < 0.05). These results verify the theory that the use of an unstable surface increases the activation of global and local trunk muscles during bridging exercises in the supine and prone positions. In conclusion, the use of BSE in a rehabilitation program may have therapeutic effects for patients with LBP by increasing trunk muscle activation.

Key points

• Compared with the BBE and NBE, the BSE increased the %MVIC values of the IO, RA, MF, and ES muscles in the supine and prone positions in the patients with LBP.
• We verified that activation of the global and local trunk muscles was increased by the use of unstable surfaces during the bridging exercises in the supine and prone positions.
• The BSE was shown to be an effective exercise method for patients with LBP in a rehabilitation program by increasing trunk muscle activation.

Key words: Sling, bridging exercise, sEMG, local trunk muscle, global trunk muscle     

Physical Activity and Risk Factors for Hip Fractures in Thai Women

Hip fractures are among the most important causes of ill health and death among elderly people. Several potentially modifiable risk factors have been reported. Most claimed physical activity as a promising, inexpensive preventive measure for hip fracture. However, knowledge about risk factors for hip fracture in Asian populations is very limited. We therefore conducted a case–control study to assess the relationships between physical activity and risk of hip fractures in Thai women. From 14 hospitals in Thailand, 229 cases with a radiologically confirmed first hip fracture were enrolled. Two hundred and twenty-four controls were randomly recruited from the same neighborhood and were matched to the cases by age within a 5 year range. Information on physical activity as well as other potential confounders was obtained through personal interviews. Multivariate logistic regression revealed that past physical activity was protective in both very active and active women (OR = 0.67, 95% CI = 0.40–1.12 for moderately active women and OR = 0.20, 95% CI = 0.10–0.38 for very active women; p value for trend <0.01). Recent physical activity reduced the risk to about two-thirds (OR = 0.33, 95% CI = 0.19–0.60 and OR = 0.35, 95% CI = 0.18–0.69 for moderately and very active women respectively). In addition, breastfeeding was identified to be a protective factor (OR = 0.87, 95% CI = 0.80–0.94). In contrast, the following risk factors were identified: current use of antihistamine (OR = 13.96, 95% CI = 1.38–141.13) or traditional medicine (OR = 7.66, 95% CI = 2.71–21.63), underlying cerebrovascular diseases (OR = 6.53, 95% CI = 2.10–20.34), history of fracture (OR = 4.04, 95% CI = 1.26–12.99), parental Chinese racial background (OR = 2.52, 95% CI = 1.49–4.23), alcohol consumption (OR = 2.30, 95% CI = 1.04–5.09). Received: 14 April 2000 / Accepted: 17 October 2000     

Multicomponent Training Program with Weight-Bearing Exercises Elicits Favorable Bone Density,Muscle Strength,and Balance Adaptations in Older Women

Physical exercise is advised as a preventive and therapeutic strategy against aging-induced bone weakness. In this study we examined the effects of 8-month multicomponent training with weight-bearing exercises on different risk factors of falling, including muscle strength, balance, agility, and bone mineral density (BMD) in older women. Participants were randomly assigned to either an exercise-training group (ET, n = 30) or a control group (CON, n = 30). Twenty-seven subjects in the ET group and 22 in the CON group completed the study. Training was performed twice a week and was designed to load bones with intermittent and multidirectional compressive forces and to improve physical function. Outcome measures included lumbar spine and proximal femoral BMD (by dual X-ray absorptiometry), muscle strength, balance, handgrip strength, walking performance, fat mass, and anthropometric data. Potential confounding variables included dietary intake, accelerometer-based physical activity, and molecularly defined lactase nonpersistence. After 8 months, the ET group decreased percent fat mass and improved handgrip strength, postural sway, strength on knee flexion at 180°/s, and BMD at the femoral neck (+2.8%). Both groups decreased waist circumference and improved dynamic balance, chair stand performance, strength on knee extension for the right leg at 180°/s, and knee flexion for both legs at 60°/s. No associations were found between lactase nonpersistence and BMD changes. Data suggest that 8 months of moderate-impact weight-bearing and multicomponent exercises reduces the potential risk factors for falls and related fractures in older women.     

Trunk Muscle Activities During Abdominal Bracing: Comparison Among Muscles and Exercises

Abdominal bracing is often adopted in fitness and sports conditioning programs. However, there is little information on how muscular activities during the task differ among the muscle groups located in the trunk and from those during other trunk exercises. The present study aimed to quantify muscular activity levels during abdominal bracing with respect to muscle- and exercise-related differences. Ten healthy young adult men performed five static (abdominal bracing, abdominal hollowing, prone, side, and supine plank) and five dynamic (V- sits, curl-ups, sit-ups, and back extensions on the floor and on a bench) exercises. Surface electromyogram (EMG) activities of the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinae (ES) muscles were recorded in each of the exercises. The EMG data were normalized to those obtained during maximal voluntary contraction of each muscle (% EMGmax). The % EMGmax value during abdominal bracing was significantly higher in IO (60%) than in the other muscles (RA: 18%, EO: 27%, ES: 19%). The % EMGmax values for RA, EO, and ES were significantly lower in the abdominal bracing than in some of the other exercises such as V-sits and sit-ups for RA and EO and back extensions for ES muscle. However, the % EMGmax value for IO during the abdominal bracing was significantly higher than those in most of the other exercises including dynamic ones such as curl-ups and sit-ups. These results suggest that abdominal bracing is one of the most effective techniques for inducing a higher activation in deep abdominal muscles, such as IO muscle, even compared to dynamic exercises involving trunk flexion/extension movements.

Key Points

• Trunk muscle activities during abdominal bracing was examined with regard to muscle- and exercise-related differences.
• Abdominal bracing preferentially activates internal oblique muscles even compared to dynamic exercises involving trunk flexion/extension movements.
• Abdominal bracing should be included in exercise programs when the goal is to improve spine stability.

Key words: Static and dynamic exercises, electromyogram, voluntary co-contraction, muscle- and exercise-related differences     

Comparison of Three Bone Densitometry Methods in Osteoporotic Women

Three techniques of bone mass measurement were evaluated in the diagnosis of postmenopausal osteoporosis; the overlap in the measurements and the capacity for discriminating was determined among 51 postmenopausal normal (mean age 66.6 ± 8.4 years) and 42 postmenopausal osteoporotic women (mean age 68.5 ± 7.5 years). All bone mass was evaluated by total body bone mineral content (BMC_TB), density (BMD_TB), ultrasound bone velocity (UBV) in proximal phalanxes 2–5 of the nondominant hand (UBV = mean value of all ultrasound measurements), and peripheral quantitative computed tomography of the nondominant forearm (pQCT). BMC_TB was found to be significantly better (P < 0.0001) for diagnosing postmenopausal osteoporosis than the other methods; both cortical and trabecular pQCT measurements were more discriminating than the corresponding UBV measurements (P < 0.001). T-score values in normals, subjects versus osteoporotic ones were BMC_TB−1.15 ± 0.79 versus −3.17 ± 0.74; BMD_TB−1.01 ± 0.97 versus −3.28 ± 0.81; UBV −1.51 ± 1.02 versus −2.34 ± 1.21; trabecular-pQCT −0.40 ± 0.72 versus −1.57 ± 0.37; cortical-pQCT −1.00 ± 0.87 versus −2.67 ± 0.53; and total-pQCT −0.65 ± 1.01 versus −2.34 ± 0.27, respectively. The overlap in values between the postmenopausal normal and postmenopausal osteoporotic groups was 50% with UBV, 6% with BMC_TB, 9% with BMD_TB, 25% with cortical pQCT, and 42% with trabecular pQCT. BMC_TB, BMD_TB, UBV, and pQCT correlated well with each other as measurements of bone mass, but BMC_TB was more discriminating than the other measurements in the diagnosis of osteoporosis. Received: 7 June 1995 / Accepted: 21 May 1997     

The Use of Perineal Ultrasound to Quantify Levator Activity and Teach Pelvic Floor Muscle Exercises

Perineal ultrasound was used to detect and quantify levator activity by measuring the displacement of the internal urethral meatus against the inferoposterior margin of the symphysis pubis. Women who had previously been instructed in pelvic floor muscle exercises were more likely to contract the levator muscle when asked to do so than were those without previous instruction (P<0.0001). Of the 56 women who were unable to contract the pelvic floor on request, 32 (57%) eventually succeeded with visual ultrasound biofeedback. Pelvic floor muscle assessment and teaching can be used as an adjunct to the ultrasound assessment of urogynecologic patients, requiring at most 5 minutes. It allows quantification of lavator activity and can provide visual biofeedback, which is easily understood and readily accepted by women.     

Dual Hip Bone Mineral Density in Postmenopausal Women: Geometry and Effect of Physical Activity

The objectives of this study were to (1) obtain both femoral neck strength (FNS) and hip axis length (HAL) values from left and right femurs (regardless of hip dominance) measured by DXA and evaluate their relationship with BMD of all hip regions including total hip, (2) determine if there is a difference between dominant and nondominant hip BMD in any of the hip regions, and (3) determine how physical activity influences hip BMD. Participants were 136, generally healthy Caucasian women (57.4–88.6 years). BMD was measured by DPX-MD. Past and present activity was assessed by the Allied Dunbar National Fitness Survey for older adults and normal/brisk walking pace was measured in a straight hallway. FNS analysis uses femoral geometry to calculate stresses at the femoral neck for two loading conditions: Safety Factor Index (SF) indicates risk of fracture for forces generated during a one-legged stance, and Fall Index (FI) indicates risk of fracture for forces generated during a fall on the greater trochanter. Simple and multiple regression analyses were used to determine predictive ability of HAL, SF, and FI for respective hip BMD values. There was no statistical difference in BMD between two hips in any of the measured regions, however, the nondominant hip correlated better with other skeletal sites. Subjects with a faster normal walking speed had higher neck BMD in the nondominant hip, 0.832 ± 0.12 vs. 0.791 ± 0.10 g/cm² (P < 0.05). Longer HAL of the left hip was negatively related to neck, trochanter, shaft, and total hip BMD. FI was significantly associated with all sites of the hip BMD, while SF was associated only with neck and wards BMC (P < 0.05). In summary: (1) a longer HAL is associated with lower BMD and a higher FI with higher BMD, (2) it might be sufficient to measure BMD in only the nondominant hip, and (3) walking at a faster pace may positively benefit femoral neck BMD. Therefore, it appears that HAL, SF, and FI all play important roles in estimating fracture risk and should be assessed along with BMD when using DXA.     

Conservative Treatment with Active Exercises in Osteoarthritis of the Hip

Six patients with cubitus varus deformity after a supracondylar fracture of the humerus had ulnar nerve palsy 7 (3–14) years following the fracture. All the patients showed anterior dislocation of the ulnar nerve during elbow flexion. In cubitus varus deformity, medial shifting of the triceps muscle occurs, which pushes the ulnar nerve anteriorly and frequently causes ulnar-nerve dislocation. Five of the 6 patients under-went surgery with subsequent improvement.     

Intraoperative Muscle Damage in Total Hip Arthroplasty

Tenderness in the medial and posterior thigh is sometimes observed during the early postoperative period after total hip arthroplasty (THA). In this study, the possible correlations of preoperative hip range of motion, surgical approach, and limb lengthening with postoperative muscle strain injury in THA were investigated. Sixty primary THA patients given the posterolateral approach or direct-lateral approach were examined. For comparison of the muscle strain injury in the 2 groups, we used magnetic resonance imaging. There were significant differences in postoperative thigh pain between cases in the posterolateral group with reduction of internal rotation and those with no reduction, and between cases in the direct-lateral group with reduction of external rotation and those with no reduction.     

重度先髋脱位全髋置换术中肢体延长长度的探讨

目的探讨全髋关节置换术(total hip arthroplasty,THA)治疗重度先天性髋关节脱位(developmental dys-plasia hip,DDH)时下肢可以延长的安全范围。方法基础研究部分:20只狗建立后肢延长后神经、血管损伤模型,通过神经电生理、组织学和血流动力学的方法,了解其神经损伤和血管损伤与牵拉的关系。临床研究部分:29例(32髋)重度DDH患者,26髋行单纯THA手术,6髋行THA、粗隆下截骨术。术后采用Harris评分、肌电图、血管超声等方法检查神经血管损伤,平均随访6个月。结果动物实验:延长长度超过肢体原有长度6%时,神经电生理有所表现,未发生血管损伤。临床试验:29例患者术前Harris评分为(32.98±8.51)分,术后随访6周,28例患者(脱漏1例)Harris评分为(91.26±3.57)分,肢体延长长度(3.3±1.15)cm,最长延长5.9 cm。有5例出现神经传导速度减慢,6例出现感觉神经传导减慢,4例延长超过下肢长度6%的患者均出现感觉及运动神经传导异常、肌电图未见自发电位,3例患者在术后出现肢体麻木,复诊时症状消失;血管损伤均未发生。结论 THA手术治疗重度DDH时,肢体延长不超过下肢长度的6%是安全的。     

Hip Fractures Risk in Older Men and Women Associated With DXA‐Derived Measures of Thigh Subcutaneous Fat Thickness,Cross‐Sectional Muscle Area,and Muscle Density

Mid‐thigh cross‐sectional muscle area (CSA), muscle attenuation, and greater trochanter soft tissue thickness have been shown to be independent risk factors of hip fracture. Our aim was to determine whether muscle and adipose tissue measures derived from dual‐energy X‐ray absorptiometry (DXA) scans would have a similar risk association as those measured using other imaging methods. Using a case‐cohort study design, we identified 169 incident hip fracture cases over an average of 13.5 years among participants from the Health ABC Study, a prospective study of 3075 individuals initially aged 70 to 79 years. We modeled the thigh 3D geometry and compared DXA and computed tomography (CT) measures. DXA‐derived thigh CSA, muscle attenuation, and subcutaneous fat thickness were found to be highly correlated to their CT counterparts (Pearson's r = 0.82, 0.45, and 0.91, respectively; p < 0.05). The fracture risk of men and women were calculated separately. We found that decreased subcutaneous fat, CT thigh muscle attenuation, and appendicular lean mass by height squared (ALM/Ht²) were associated with fracture risk in men; hazard ratios (HR) = 1.44 (1.02, 2.02), 1.40 (1.05, 1.85), and 0.58 (0.36, 0.91), respectively, after adjusting for age, race, clinical site, body mass index (BMI), chronic disease, hip bone mineral density (BMD), self‐reported health, alcohol use, smoking status, education, physical activity, and cognitive function. In a similar model for women, only decreases in subcutaneous fat and DXA CSA were associated with hip fracture risk; HR = 1.39 (1.07, 1.82) and 0.78 (0.62, 0.97), respectively. Men with a high ALM/Ht² and low subcutaneous fat thickness had greater than 8 times higher risk for hip fracture compared with those with low ALM/Ht² and high subcutaneous fat. In women, ALM/Ht² did not improve the model when subcutaneous fat was included. We conclude that the DXA‐derived subcutaneous fat thickness is a strong marker for hip fracture risk in both men and women, especially in men with high ALM/Ht². © 2015 American Society for Bone and Mineral Research. © 2015 American Society for Bone and Mineral Research     

Comparison of Bone Mineral Density of the Phalanges, Lumbar Spine, Hip, and Forearm for Assessment of Osteoporosis in Postmenopausal Women

The objective of this study was to compare peripheral bone mineral density (BMD) of the phalanges with BMD of the lumbar spine, total hip, femoral neck, and forearm and to determine the clinical value of measuring a single peripheral site (phalanges) in identifying postmenopausal women with osteoporosis. BMD was measured by dual energy X-ray absorptiometry using the accuDEXA((R)) (ADXA-finger) (Schick, New York, NY) and the QDR-4500 (DXA-lumbar spine, hip, forearm) (Hologic, Waltham, MA). Correlation coefficients between ADXA and DXA of the lumbar spine, total hip, femoral neck and one third radial site ranged from 0.53 to 0.73. The sensitivity of an ADXA T-score of -2.5 in identifying patients with a DXA T-score of < or = -2.5 at the femoral neck was 35%. An ADXA T-score cut point of -1.0 improved the sensitivity of ADXA in identifying patients with a femoral neck T-score of < or = -2.5 (85%), but the specificity declined from 88 to 49%. There was substantial discordance in the diagnosis of osteoporosis when a single site was measured, regardless of technique. Within the limitations of single-site measurements, BMD measured by ADXA has adequate sensitivity to identify women with low BMD at the femoral neck, if an appropriate T-score criterion is used.     

Pelvic Muscle Exercise Effect on Pelvic Muscle Performance in Women

The aim of this study was to compare pelvic muscle (PM) characteristics (strength, endurance and contractability) before and after 12 weeks of pelvic muscle exercises in two groups of older women: the first composed of women with genuine stress incontinence, and the second made up of women with no symptoms of urinary incontinence or pelvic organ prolapse. This research also investigated the extent to which PM pressure and health-related characteristics could help discriminate between women with and without a clinical sign of PM dysfunction. Within a framework of skeletal muscle fitness, outcome measures were defined and compared. There was no significant difference in the baseline (P= 0.09) and post-PME (P= 0.63) strength, endurance and contractability of the two groups of women. The two groups did differ significantly on change scores (P= 0.05) following PME. A greater improvement in strength for women without a clinical sign of dysfunction was demonstrated. There was a probability of 91% that those with a history of gynecological surgery belonged to the group of women with SUI.     

3种脂肪氧合酶酶活测定方法

采用量压法、分光光度法和KI-淀粉法测定了一系列经不同程度热处理的脂肪氧合酶酶活力.分析了3种方法的优缺点和相关性，结果表明相关性良好，其中，量压法具有最广泛的酶液适用性，分光光度法灵敏度最高，KI-淀粉法更适合于工业化应用.