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Effects of Hydraulic-Resistance Exercise on Strength and Power in Untrained Healthy Older Adults
Abstract
The purpose of this study was to determine the efficacy of hydraulic-resistance exercise (HDRE) in improving strength and power in healthy older adults. Thirty-nine older adults (68.6 ± 4.9 years; 15 men, 24 women) were divided into a training group or control group (CON). Hydraulic-resistance exercise consisted of a 12-week supervised program, 50 min · d(-1), 3 d · wk(-1). Hydraulic-resistance exercise was used for 10 exercises: Chest press and pull, shoulder press and pull, low back flexion and extension squat, leg adduction/abduction, leg press, and elbow extension/flexion. The number of the sets and the hydraulic-resistance dial setting (D) were gradually increased in 3 stages during the 12-week program. Strength, rating of perceived exertion, and relative intensity during exercise increased significantly from stage to stage whereas repetition velocity decreased. Total work was higher in the second stage compared with the first but lower in the final stage because of reduced repetitions. Peak torque at D2 and D11 increased (p < 0.05) for knee extension (58 and 9%) and flexion (94 and 21%), chest press (35 and 12%) and pull (29 and 14%), shoulder press (14 and 18%) and pull (75 and 18%), and low back flexion (59 and 46%) and extension (84 and 34%). Peak power at D2 and D11 also increased (p < 0.05) for knee extension (140 and 26%) and flexion (96 and 36%), chest press (54 and 28%) and pull (62 and 23%), shoulder press (55 and 31%) and pull (159 and 30%), and low back flexion (177 and 127%) and extension (104 and 66%). There were no significant changes in the CON. Hydraulic-resistance exercise elicits significant improvements in strength and power in older adults. Therefore, HDRE is an effective form of resistance training that provides benefits using low and moderate intensity of training for older adults.
... Aerobik destekli döngüsel direnç egzersizleri vücudun, farklı kas gruplarını içeren alternatif sürelere uyum sağlaması açısından tercih edilebilir bir yöntem olabilir. 6,7,8 Konvansiyonel egzersizlerin uzamasından kaynaklanan kardiyovasküler tehlikeleri en aza indirgeyecek program yapısına sahiptir. 8 Döngüsel direnç egzersiz programı, yetişkinler ve yaşlılar için güvenlidir, çünkü eğitim sırasında yaralanma riski çok azdır. ...
... 6,7,8 Konvansiyonel egzersizlerin uzamasından kaynaklanan kardiyovasküler tehlikeleri en aza indirgeyecek program yapısına sahiptir. 8 Döngüsel direnç egzersiz programı, yetişkinler ve yaşlılar için güvenlidir, çünkü eğitim sırasında yaralanma riski çok azdır. Ayrıca egzersize bir grup olarak katılmak, programlara katılımı devam ettirme isteğini arttırarak kişilerde psikolojik ve sosyal faydalara sebep olabilir. ...
... Ayrıca egzersize bir grup olarak katılmak, programlara katılımı devam ettirme isteğini arttırarak kişilerde psikolojik ve sosyal faydalara sebep olabilir. 8,9,10 Amerikan Spor Hekimliği Birliği, kilo vermek için haftada 150 ila 250 dakika egzersiz yapılmasını önermekle birlikte alternatif olarak haftada 3 gün 20-60 dakika şiddetli egzersiz programlarının da uygun olabileceğini belirtmektedir. 11 Zamanın önem kazandığı günümüzde sağlıklı kalmak ve kilo vermek için az zaman harcayarak en etkili yöntemi seçmek önem arz etmektedir. ...
Amaç: Çalışmamızın amacı fazla kilolu ve obez kadın katılımcılarda, 30 dakika süren aerobik egzersizle kombine edilmiş döngüsel direnç egzersizlerinin, vücut kompozisyonu üzerindeki etkilerini belirlemektir.Gereç ve Yöntem: Bu çalışma yaşları 20-54 yıl arasında (30,14±10,62 yıl) 50 sağlıklı kadın ile gerçekleştirilmiştir. Katılımcılar beden kitle indeksine göre fazla kilolu ve obez olmak üzere iki gruba ayrıldı. Katılımcıların demografik verileri ile vücut kompozisyon değerleri egzersiz öncesinde ve sonrasında kaydedildi. Katılımcılar, haftada 3 gün, 12 hafta egzersiz programına alındı.Bulgular: Katılımcılarda kilo verme ve vücut kompozisyon değerlerindeki gelişmeler açısından bu tip egzersizlerin etkili olduğu görülmüştür (p=0,001). Gruplar karşılaştırıldığında obez grupta kilo (p=0,002) ve iç yağ oranı (p=0,005) kaybının daha fazla olduğu bulunmuştur.Sonuç: Otuz dakika süren aerobik egzersizle kombine döngüsel direnç egzersizler kilo verme amaçlı kullanılabilecek kısa süreli, etkili bir alternatiftir.
... [11][12][13] ，HDL コレステロールの増加や体脂肪の減少 11,13) ， 認知機能の改善 14) ，あるいは日常身体活動量の増加 10 Table 4 Values are means ± SD, CRT: circuit gym using group, WALK: walking group, BMI: body mass index, SBP: systolic blood pressure, DBP: diastolic blood pressure. Values are means ± SD, *p<0.05 vs PRE (Bonferroni correction). ...
... ，HDL コレステロールの増加や体脂肪の減少 11,13) ， 認知機能の改善 14) ，あるいは日常身体活動量の増加 10 Table 4 Values are means ± SD, CRT: circuit gym using group, WALK: walking group, BMI: body mass index, SBP: systolic blood pressure, DBP: diastolic blood pressure. Values are means ± SD, *p<0.05 vs PRE (Bonferroni correction). ...
This study examined the effects of a 6-month circuit gym workout on muscle and fat cross-sectional area (CSA) and muscle strength in middle-aged and older women. The participants were 49 women without severe metabolic disease, exercise limitation, or exercise habits. They were randomly assigned to two groups, circuit gym using group (CRT: n = 25) and walking group (WALK: n = 24). Both groups followed the exercise program for 6 months. Thigh and abdominal CSA before and after the program were measured using magnetic resonance imaging. Moreover, knee extensor/flexor and hip flexor strength were measured using a dynamometer. After completion of the exercise program, CSA of the psoas major muscle and isokinetic knee and hip flexion strength significantly increased in the CRT group compared with the WALK group (CSA: 7.1% vs 1.4% respectively; isokinetic strength: 7.5% vs −4.3% (knee), 23.6% vs 2.2% (hip), respectively). In addition, subcutaneous adipose tissue of the thigh in the CRT group significantly decreased compared with that in the WALK group (−6.5% vs −1.8%, respectively). These results imply that in middle-aged and older women, the use of circuit gym leads to a more effective increase in CSA of the psoas major muscle, decrease in thigh subcutaneous adipose tissue, and increase in knee and hip flexor strength compared with brisk walking. © 2018 Japanese Society of Physical Fitness and Sports Medicine. All rights reserved.
... The Control team did not go through preparation. (Lee et al., 2011). ...
Objective Technical knowledge is challenging old beliefs and myths about health, leading to a better understanding of how to lead a healthy life beyond just the absence of illness. Women's health management is gaining global attention due to the increasing health issues associated with modern lifestyles. Health is not just about being free from illness but also having enough strength and energy to exercise daily and proper functioning of different body systems. A study aimed to investigate the insulated and united influence of hydraulic resistance training and ladder agility training on the lipid profile of working women. Methods The study consisted of 60 healthy untrained women aged 25 to 32 years, who were randomly assigned to one of four teams: investigational Team 1 (hydraulic resistance training), investigational Team 2 (ladder agility training), investigational Team 3 (a combination of hydraulic resistance and ladder agility training), and control Team. The investigational Teams participated in eight weeks of training, while the control Team did not undergo training. Results The mean values and statistical test results for Total Cholesterol (TCL), Low-density Lipoprotein cholesterol (LDL), and High-density Lipoprotein Cholesterol (HDL) levels for four different Teams before and after an intervention. The adjusted after-test mean values were highest in the CHRLATG Team, indicating that the combined hydraulic resistance and ladder agility training intervention may have been the most effective in reducing TCL and LDL and increasing HDL levels. Conclusion The study found that hydraulic resistance and ladder agility training significantly affected the lipid profile of working women, with the HRTG/LATG Team having lower mean values for LDL and higher mean values for HDL than the control Team. These findings suggest that HRTG/LATG may be an effective intervention for improving lipid profiles among working women, although further studies are needed to confirm these outcomes and investigate long-term effects.
... The exercise program used in this study complied with the guidelines for physical activity for cancer survivors of the US Department of Health and Welfare and the American Society of Sports Medicine [30,31]. The HCRE program for FBCSs was modified and supplemented with the circuit resistance exercise program used in the studies by Lee et al. [32] and Ballor et al. [33]. The HCRE program consisted of warm-up (walking and stretching, 10 min), main exercise (30 min), and cool-down (stretching, 10 min). ...
Questions remain about whether resistance exercise has a positive effect on immune and inflammatory cells. The purpose of this study was to evaluate the effect of 12 weeks of high-intensity circuit resistance exercise (HCRE) on inflammation and immune cells, and physical fitness, of female breast cancer survivors (FBCSs). Thirty FBCSs were randomly assigned to the HCRE (n = 15) and control (n = 15) groups. HRCE was administered for 50 min a day, 2–3 times a week, for 12 weeks. The control group only performed activities of daily living during the study period. Baseline and post-intervention measures included body composition, muscular strength, muscular endurance, flexibility, reaction time, balance, inflammation, and immune cell measurements. The results showed that HCRE improved body mass index, body fat, muscle mass, grip strength, back muscle strength, sit-up, whole-body reaction, standing on one leg with eyes closed, Y-balance test, and NKCA in FBCSs. The improvement of physical strength and immune cells of FBCSs was achieved using the 12-week HRCE program. Future studies must analyze various exercise intensities and types, and should be conducted on other cancer survivors. In addition, strategies should be developed to allow FBCSs to participate in resistance training.
... Resistance training (RT) can increase muscle strength [15], improve functional ability [16] and eliminate most age-associated sarcopenia in a healthy population [17,18]. Other studies also revealed that RT can help improve RFD in healthy young [19] and elderly individuals [20]. ...
Dynamic combined training is a crucial component in treating musculoskeletal conditions to increase muscle strength and improve functional ability. This randomized control trial aimed to examine the effect of dynamic combined training on muscle strength and contractile rate of force development (RFD) in patients with osteoporosis (OP) and knee osteoarthritis (KOA). 58 participants with OP or KOA were randomly assigned to a control group (CG) (CGOP, n = 12; CGKOA, n = 15) or training group (TG) (TGOP, n = 14; TGKOA, n = 17). The training group participated in a 12-week, three-days-per-week supervised program consisting of stretching and warm-up exercises (10 min), hydraulic resistance training (40 min), and cool-down and relaxation exercises (10 min). All participants were evaluated at baseline and post-training. The maximal voluntary contraction (MVC) and contractile RFD at 0–200 ms increased significantly in middle-aged and older patients with OP. As for KOA, the dynamic combined training program was effective in improving the muscle strength. The maximal voluntary contraction (MVC) and contractile RFD at 0–200 ms increased significantly (by 29.22%, P = .000 and 27.25%, P = .019, respectively) in middle-aged and older patients with OP. In the KOA group, MVC and contractile RFD improved but did not reach statistical significance. The dynamic combined training program is effective for health promotion in older adults with OP or KOA.
... However, low exercise intensities similar to those used in early studies promote only modest increases in strength in older subjects [5,6] . Several studies have since demonstrated that, given an adequate training stimulus, resistance training provides similar or greater strength gains in older men and women compared to younger individuals [7][8][9] . ...
Health upholds physical nicely-being, Happiness, harmony, Peace sooner or afterobtains humanity, and fitness ends in the well-being of the whole thing. The ideal of study was find out the effect of hydraulic training on selected physical fitness variables among college women studentsof Karpagam Academy of Higher Education, Coimbatore. 30 untrained volunteers from KAHE were taken to participate in the study. Their age ranged from 18 to 24 years. They were randomly divided and assigned into two groups of fifteen each such as experimental group (hydraulic training group) 1(n=15and control group 2 (n=15). The experimental groups underwent hydraulic training and the control group did not undergo any special training except their leisure time pursuit as college women students. The data were collected before and after the training period of 12 weeks and the data collected were statically analysed by paired t-test, which was used to find out the significant improvement on selected parameters of pre-test and post-test means of the experimental and control group on each parameter separately. The result shows that there was a significant improvement in speed, Strength and endurance.
The main objective of our study is to analyze the effect of resistance and flexibility exercise intervention on balance in older adults. Balance is the ability to maintain an upright posture during static and dynamic tasks. Maintaining balance involves a complex interaction between intrinsic factors, including peripheral, visual and vestibular sensation and muscle factors, and the interplay between the neural network and motor output, which are processed and mediated centrally. Programs to increase physical exercise among elderly persons have been found to be beneficial to health. Evidence suggests that training should combine both flexibility exercises and resistance exercises. Berg Balance Scale was the outcome measure. Twenty subjects were selected and divided into two groups. Group A (10 subjects) were given Resisted exercises for 40-45 minutes with two sets of 10 – 12 repetitions for ten weeks. Group B (10 subjects) were given flexibility exercises for 40-45 minutes and included 10–12 repetitions for ten weeks. On comparing the mean values of Group A & Group B on the Berg Balance Scale score, it shows a significant increase in the post-test mean values in both groups, but (Group A - Resistance Exercise) shows 51.10 which has the higher Mean value is effective than (Group B - Flexibility exercise) 46.40 at P ≤ 0.001. Comparing Pretest and Posttest within Group A & B on the Berg Balance Scale score shows a highly significant difference in mean values at P ≤ 0. 001. This study concludes that resisted exercise significantly improved balance in older adults than in flexibility exercise.
Background
The body's potential for characteristic; health became visible as a state of regular function that would be disrupted from time to time through disorder. The purpose of this study was to determine the isolated and combined effect of hydraulic and ladder training on total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol among college women students.
Methods
Totally 60 untrained volunteers from KAHE were taken to participate in the study. Their age ranged from 18 to 24 years. They were randomly divided and assigned into three groups of fifteen each as the experimental group (hydraulic training) 1(n = 15), experimental group (ladder training) 2 (n = 15), experimental group (hydraulic and ladder training) 3(n = 15) and control group 1 (n = 15). The data were collected before and after the training period of 12 weeks and the data collected were statically analysed which was used to find out the significant improvement on selected parameters and analysis of variance (ANOVA) was used to find out the significant difference if any among the adjusted post-test means of the experimental and control group on each parameter separately.
Results
The Statistical analysis of the hydraulic training group, ladder training group, combined training group, and the control group of F ratio. The obtained f ratio of total cholesterol is 41.01, low-density lipoprotein is 40.44 and high-density lipoprotein cholesterol is 31.59 of post-test was greater than the table value of the degree of freedom 3,56 required for the significance at 0.05 level. The combined training group responded to the training with a more positive influence on low-density lipoprotein, and high-density lipoprotein cholesterol, when compared with the hydraulic training group, ladder training group, control group, and the hydraulic training group, the ladder training group was better than the control group.
Conclusion
It concluded that the study significantly improved that the combined training of hydraulic and ladder training was a better improvement in their level of total cholesterol, low-density lipoprotein, and high-density lipoprotein cholesterol and enhance their daily activity level of fitness also improved and better lifestyle.
Objective
The body's potential for characteristic; health became visible as a state of regular function that would be disrupted from time to time through disorder. The purpose of this study was to determine the isolated and combined effect of hydraulic and ladder training on total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol among college women students.
Methods
Totally 60 untrained volunteers from KAHE were taken to participate in the study. Their age ranged from 18 to 24 years. They were randomly divided and assigned into three groups of fifteen each as the experimental group (hydraulic training) 1(n = 15), experimental group (ladder training) 2 (n = 15), experimental group (hydraulic and ladder training) 3(n = 15) and control group 1 (n = 15). The data were collected before and after the training period of 12 weeks and the data collected were statically analysed which was used to find out the significant improvement on selected parameters and analysis of variance (ANOVA) was used to find out the significant difference if any among the adjusted post-test means of the experimental and control group on each parameter separately.
Results
The Statistical analysis of the hydraulic training group, ladder training group, combined training group, and the control group of F ratio. The obtained f ratio of total cholesterol is 41.01, low-density lipoprotein is 40.44 and high-density lipoprotein cholesterol is 31.59 of post-test was greater than the table value of the degree of freedom 3,56 required for the significance at 0.05 level. The combined training group responded to the training with a more positive influence on low-density lipoprotein, and high-density lipoprotein cholesterol, when compared with the hydraulic training group, ladder training group, control group, and the hydraulic training group, the ladder training group was better than the control group.
Conclusion
It concluded that the study significantly improved that the combined training of hydraulic and ladder training was a better improvement in their level of total cholesterol, low-density lipoprotein, and high-density lipoprotein cholesterol and enhance their daily activity level of fitness also improved and better lifestyle.
The purpose of this study was to assess the influence of leg power and leg strength on the physical performance of community-dwelling mobility-limited older people.
Cross-sectional analysis of baseline data from a 12-week randomized controlled exercise-intervention study.
Exercise laboratory within the Department of Health Science of an urban university.
Forty-five community-dwelling mobility-limited people (34 women, 11 men), aged 65 to 83.
Health status, depression, cognition, physical activity, and falls efficacy; physiological measures of lower extremity strength and power; and measures of physical performance.
Through bivariate analyses, leg power was significantly associated with physical performance as measured by stair-climb time, chair-stand time, tandem gait, habitual gait, maximal gait, and the short physical performance battery describing between 12% and 45% of the variance (R2). Although leg power and leg strength were greatly correlated (r = .89) in a comparison of bivariate analyses of strength or power with physical performance, leg power modeled up to 8% more of the variance for five of six physical performance measures. Despite limitations in sample size, it appeared that, through quadratic modeling,the influence of leg power on physical performance was curvilinear. Using separate multivariate analyses, partial R2 values for leg power and leg strength were compared, demonstrating that leg power accounted for 2% to 8% more of the variance with all measures of physical performance.
Leg power is an important factor influencing the physical performance of mobility-limited older people. Although related to strength, it is a separate attribute that may exert a greater influence on physical performance. These findings have important implications for clinicians practicing geriatric rehabilitation.
Mechanisms and structures which are involved in eccentric exercise-induced delayed onset muscle soreness (DOMS) are not yet clarified. Tissue and site specificity may be important considerations in afferent sensitisation following eccentric exercise. This study investigated the nociceptive response to hypertonic sodium solution applied to fascial/epimysium tissue and mechanically sensitised sites in muscle by assessing (1) afferent recordings in animals and (2) psychophysical assessment in humans. Seventeen male rats underwent eccentric contraction of extensor digitorum longus muscle, while 11 rats served as an unexercised naïve group. Two days post-exercise, group IV afferent fibre activity was recorded in response to superfusion of hypertonic Krebs solution on the mechanically sensitised muscle/epimysium site. Mechanical sensitisation was confirmed with significant increases in afferent response and decreases in threshold to mechanical stimulation in the eccentrically exercised rats compared to naïve rats. There was no difference in afferent response magnitude to hypertonic Krebs solution between exercise and naïve groups. In the human study, 13 volunteers participated. After bilateral assessment of pressure pain thresholds (PPT) along the tibialis anterior muscles, eccentric exercise was performed to induce DOMS in m. tibialis anterior of one leg. Site of maximal mechanical sensitivity was identified 24 h later and injected with hypertonic saline at fascial and deep muscle levels. The corresponding site on the opposite unexercised leg served as a control. Fascial injection of the exercised muscle caused significantly higher pain intensity compared to all other injections. Response to deep muscle stimulation was not different between sides. This suggests that fascia rather than muscle tissue is important in DOMS associated sensitisation.
To determine the effect of training intensity on the contributions of force and velocity to improvements in peak power (PP) after explosive resistance training in older adults.
112 healthy older adults (69 +/- 6 yr) were randomized to explosive resistance training at 20% (G20), 50% (G50), or 80% (G80) maximal strength (1-repetition maximum) for 8-12 wk (twice weekly, 5 exercises, 3 sets of 8 explosive concentric/slow eccentric repetitions) using pneumatic resistance machines or a nontraining control group (CON).
Force at peak power (FPP) increased significantly and similarly among training groups compared with CON. Velocity at peak power (VPP) did not improve significantly and remained similar between all groups. Force contributed significantly more to PP production in G80 and G50 than in CON. The change in PP was independently predicted by changes in fat-free mass in G80 and by changes in both FPP and VPP in G50 and G20.
Explosive resistance training in older adults results in the ability to produce higher PP outputs with heavier loads without loss of movement velocity. Moderate- to high-intensity training induced a greater relative contribution of force to PP production in this cohort.
The effects of strength conditioning on skeletal muscle function and mass were determined in older men. Twelve healthy untrained volunteers (age range 60-72 yr) participated in a 12-wk strength training program (8 repetitions/set; 3 sets/day; 3 days/wk) at 80% of the one repetition maximum (1 RM) for extensors and flexors of both knee joints. They were evaluated before the program and after 6 and 12 wk of training. Weekly measurements of 1 RM showed a progressive increase in strength in extensors and flexors. By 12 wk extensor and flexor strength had increased 107.4 (P less than 0.0001) and 226.7% (P less than 0.0001), respectively. Isokinetic peak torque of extensors and flexors measured on a Cybex II dynamometer increased 10.0 and 18.5% (P less than 0.05) at 60 degrees/s and 16.7 and 14.7% (P less than 0.05) at 240 degrees/s. The torque-velocity relationship showed an upward displacement of the curve at the end of training, mainly in the slow-velocity high-torque region. Midthigh composition from computerized tomographic scans showed an increase (P less than 0.01) in total thigh area (4.8%), total muscle area (11.4%), and quadriceps area (9.3%). Biopsies of the vastus lateralis muscle revealed similar increases (P less than 0.001) in type I fiber area (33.5%) and type II fiber area (27.6%). Daily excretion of urinary 3-methyl-L-histidine increased with training (P less than 0.05) by an average 40.8%. Strength gains in older men were associated with significant muscle hypertrophy and an increase in myofibrillar protein turnover.
Body composition was studied in subjects from the seventh decade of life (13 M, 25F), observations being made on recruitment and at selected points over a 1-year program of endurance training. As at younger ages, the women initially had more subcultaneous fat than the men, particularly over the limbs. In both sexes, excess weights (9.3 kg. M; 8.1 kg, F) and average skinfold radings (16.2 mm, M; 21.1mm, F) were greater than in younger adults. Edurance training (1 hr of supervised exercise, 150-200 kcal persession, nominal four sessions per week) progressively reduced skinfold readings, by an average of 1.6 mm at 7 weeks, by 2.4 dependent upon the intensity and the frequency of exercise undertaken by the individual. Total body potassium (40K determinations) agreed well with previous studies of older subjects. Body fat estimated form 40K showed a fair correlation with skinfold estimates of body fat (r=0.69, M; 0.93, F), but absolute precentages were higher by 40K(36.6%, M; 48.7%, F) than by subcutaneous fat measurements (20%, M;32% F). Body potassium increased by 4% over the year of training, 70% of this change, occurring between the 14th and the 52nd week of conditioning. Small gains were also recorded in arm circumference, grip strenght (R but not L) and knee extension force. Neutron activation data showed that both sexes had lower initial bone calcium counts than sedentary middle-aged adults. The sample as a whole showed no calcium loss over the year of training, but the group taking the least exercise did show a significant loss (P less than 0.05). Modest endurance training of an elderly population seems not only to correct loss of cardiorespiratory condition, but also to induce favorable changes in body fat and lean mass.
This study assessed the measurement reliability and validity of the Hydra-Fitness Omnitron, a microprocessor-controlled isokinetic ergometer that provides concentric resistance for dynamic extension and flexion movements as well as resistance for isometric contractions. Maximal peak torque output measured by the Omnitron and strain gauge devices connected to the apparatus were compared in 26 physically active males who were tested over 3 days for isometric knee extension and isokinetic knee flexion/extension at two resistance levels. Maximal torque outputs remained stable on days 2 and 3 (p less than 0.05), and intraclass reliability yielded r = 0.94 to 0.98. There was no difference between the slopes of the regression lines for the different experimental conditions (p less than 0.05). There was significant improvement between day 1 and days 2 and 3 that corresponded to a combination of a training and learning effect. Thus, one practice session was necessary to obtain reliable individual differences. The validity correlations between peak torque output measured from the Omnitron and strain gauges were greater than r = 0.94. There was a small discrepancy (0.44 to 0.88 Nm) between the two measuring devices that can be explained by the difference in shank pad positioning that accommodates for different segment lengths. We conclude that reliability and validity were excellent over a wide range of torque outputs measured during maximal isometric and maximal dynamic double concentric flexion and extension movements.
Neither age-related osteoporosis nor the increasing incidence of falls with age sufficiently explain the exponential increase
in the incidence of hip fracture with aging. We propose that four conditions must be satisfied in order for a fall to cause
a hip fracture: (a) the fatter must be oriented to impact near the hip; (b) protective responses must fail; (c) local soft
tissues must absorb less energy than necessary to prevent fracture, and (d) the residual energy of the fall applied to the
proximal femur must exceed its strength. All of these events become more likely with aging and lead to an exponential rise
in the risk of hip fracture with advancing age. This model also suggests that a combination of measurements of neuromuscular
function and of bone strength may be the most accurate approach to assessing the risk of hip fracture.
In order to examine the effectiveness and safety of hydraulic resistance strength training in young males, 26 pre-pubertal males (mean age = 8.2 +/- 1.3 yr) completed a 14-wk strength training study. Subjects were evaluated before and after the 14-wk experimental period for pubertal state (Tanner's sexual maturity rating, serum testosterone, and serum dihydroepiandrosterone sulfate). Effectiveness of the strength training program was determined by measuring pre-post differences in: isokinetic strength for flexion and extension at the knee and elbow joints at two speeds (30 degrees and 90 degrees X s-1) (KIN COM, Chattecx, Inc., Chattanooga, TN), flexibility, standing long jump, vertical jump, body composition parameters, maximal oxygen consumption, and creatinine phosphokinase. Safety of strength training was assessed by biphasic musculoskeletal scintigraphy before and after the program and by physician evaluation of complaints by subjects. Strength training subjects (N = 16) participated in a 45 min/session, 3 session/wk, 14-wk supervised strength training program with an attendance rate of 91.5%. Participants performed concentric work using hydraulic resistance equipment (Hydra-Fitness Industries, Belton, TX). Eccentric work was not performed. Control subjects (N = 10) did not strength train but did participate in sport activities and activities of daily living. Results indicated that strength training subjects increased isokinetic strength as a result of strength training (average concentric work/repetition increases by 18.5 to 36.6% for the eight motions tested; torque scores over the first 90% of the range of motion increases by 13.1 to 45.1% for the eight motions tested). These changes were significantly greater than changes seen in the control group (P less than 0.05). Strength training subjects also demonstrated significant improvements (as compared to control subjects) in vertical jump (+10.4%), flexibility (+8.4%), and maximal oxygen consumption [+19.4% (l X min-1), +13.8% (ml X kg X min-1)] after the experimental period. Musculoskeletal scintigraphy revealed no evidence of damage to epiphyses, bone, or muscle as a result of strength training. Only one strength training-related injury was reported (left shoulder pain, 3 strength training sessions missed). In contrast, six strength training subjects sustained injuries during activities of daily living, resulting in 47 missed strength training sessions. It was concluded that, in the short term, supervised concentric strength training using hydraulic resistance equipment is safe and effective in pre-pubertal boys.
Walking speed was measured on admission and then weekly during treatment of 125 subjects admitted to a geriatric rehabilitation
ward. Walking speed was strongly related to the ability to stand up from a chair without help. Placement decisions at discharge
were made without knowledge of gait speed data so that they could be used as a standard against which to compare walking speed
as a valid and practical measure of mobility. It was found that a discharge walking speed of 0.15 m/s best separated immobile
subjects who required long-term hospital care from those sufficiently mobile to be discharged home alone or to a rest home
(54% versus 0% below cut-off, respectively). Relative walking speed (speed/ height) was no better at predicting placement
or mortality than walking speed. Uncorrected walking speed therefore remains the preferred clinical measure of velocity. A
serial record showing improvement in walking speed proved useful in predicting eventual independent mobility of poorly mobile
subjects. Thus walking speed is an objective yet inexpensive method of monitoring gait rehabilitation.