Personalized multicomponent exercise programs using smartphone technology among older people: protocol for a randomized controlled trial.

BACKGROUND: Optimal application of the recently updated World Health Organization (WHO) guidelines for exercise in advanced age necessitates an accurate adjustment for the age-related increasing variability in biological age and fitness levels, alongside detailed recommendations across a range of motor fitness components, including balance, strength, and flexibility. We previously developed and validated a novel tool, designed to both remotely assess these fitness components, and subsequently deliver a personalized exercise program via smartphone. We describe the design of a prospective randomized control trial, comparing the effectiveness of the remotely delivered personalized multicomponent exercise program to either WHO exercise guidelines or no intervention. METHODS: Participants (n = 300) are community dwelling, healthy, functionally independent, cognitively intact volunteers aged ≥65 at low risk for serious fall injuries, assigned using permuted block randomization (age/gender) to intervention, active-control, or control group. The intervention is an 8-week program including individually tailored exercises for upper/lower body, flexibility, strength, and balance (dynamic, static, vestibular); active-controls receive exercising counselling according to WHO guidelines; controls receive no guidance. Primary outcome is participant fitness level, operationalized as 42 digital markers generated from 10 motor fitness measures (balance, strength, flexibility); measured at baseline, mid-trial (4-weeks), trial-end (8-weeks), and follow-up (12-weeks). Target sample size is 300 participants to provide 99% power for moderate and high effect sizes (Cohen's f = 0.25, 0.40 respectively). DISCUSSION: The study will help understand the value of individualized motor fitness assessment used to generate personalized multicomponent exercise programs, delivered remotely among older adults. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04181983.

Symmetries in Muscle Torque and Landing Kinematics Are Associated With Maintenance of Sports Participation at 5 to 10 Years After ACL Reconstruction in Young Men.

BACKGROUND: Long-term maintenance of sports participation is important for young men undergoing anterior cruciate ligament (ACL) reconstruction. Identifying biomechanical characteristics in patients who achieve this goal can assist in elaborating rehabilitation programs and in identifying successful recovery, but this has rarely been investigated. PURPOSE: To test the association between maintenance of sports participation at 5 to 10 years after ACL reconstruction and measures of force production and landing biomechanics in men. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 30 men who underwent isolated ACL reconstruction were examined. At 5- to 10-year follow-up, associations were tested between reported outcomes of sports maintenance and objective biomechanical measures. The biomechanical tests included isokinetic knee torque and lower limb kinetics and kinematics during landing tasks. Measurements for each limb were conducted separately, and side-to-side symmetry indices (SI) were calculated. Subgroups included SI greater than +10% (ie, extreme positive), SI lower than -10% (ie, extreme negative), and SI between -10% and +10% (ie, symmetric). RESULTS: At follow-up, concentric knee torque in the operated limb correlated with Tegner and Marx scores (r = 0.42-0.47; P ≤ .05). Regarding the SI of knee torque, the highest Tegner, Marx, and KOOS (Knee injury and Osteoarthritis Outcome Score) results were associated with symmetry, as opposed to patients with extreme positive or extreme negative SIs (P < .05). As for landing kinematics, Tegner score negatively correlated with knee range of motion (ROM) in the operated limb (r = -0.38; P ≤ .05). With regard to SI, hip and knee ROM correlated with Tegner, IKDC, and KOOS scores (r = 0.41-0.51; P ≤ .05). Specifically, the highest sports participation levels were associated with achieving symmetric hip and knee ROM but also with extreme positive SIs, as opposed to patients with extreme negative SIs (P < .03), indicating substantially higher ROM in the uninjured limb as compared with the operated limb. CONCLUSION: At 5 to 10 years after ACL reconstruction, maintenance of sports participation was associated with symmetric side-to-side concentric knee torque and with producing greater attenuation of hip and knee ROM during the drop jump landing in the operated limb. Therefore, eccentric load programs that can improve attenuation-phase kinematics during landing tasks may be valuable in addition to concentric training and may facilitate enhanced long-term outcomes.

Acute muscle stretching and the ability to maintain posture in females with adolescent idiopathic scoliosis.

BACKGROUND: Physiotherapy scoliosis specific exercises include exercises to attain and maintain proper posture, as well as flexibility movements such as stretching. OBJECTIVE: To examine the effect of prior muscle stretching on the performance of posture exercise in females with adolescent idiopathic scoliosis (AIS). METHODS: Eighteen females with AIS were randomly assigned to perform a posture maintenance task for three minutes preceded by either stretching protocol (group A) or no-stretching (group B). A second session was carried out after three days, where the same procedure was repeated in a reverse order between groups. During each session, three outcomes were tested: the ability to complete the task, the ability to maintain postural body alignment, and the perceived effort. RESULTS: All participants completed the task in both sessions. Subjects' ability to preserve the required lower trunk alignment decreased following stretching compared to no-stretching. Lower-trunk angle changed toward flexion by 10∘ and 4.3∘ respectively, p= 0.032. There was no difference in perceived effort. CONCLUSIONS: Prior muscle stretching has a negative effect on the ability to preserve body positional alignment during posture exercise. The present findings should be considered by practitioners when designing protocols for scoliosis-specific exercises. Stretching immediately prior to posture maintenance exercises should be avoided.

Isokinetic moment curve abnormalities are associated with articular knee lesions.

The aim of this study was to test whether lesions of the medial meniscus (MM) and of the anterior cruciate ligament (ACL) are associated with specific abnormalities of isokinetic moment curves (IMCs). Fifty-four young adults (20 active healthy people, and 34 patients with unilateral knee injuries) were assessed through knee extensor and flexor isokinetic tests at 60°/s. Qualitative IMC analysis was performed using a novel classification system which identified three distinct abnormal shapes. The chi-squared (χ2) test was used to determine the inter-individual and intra-individual differences between the groups. Quantitative IMC inter-group comparisons were performed by a one-way analysis of variance (ANOVA). Knees with MM and ACL lesions were consistently associated with IMC shape irregularities (p<0.001) and with abnormal quantitative scores (p<0.001). More specifically, knees with isolated ACL lesions and knees with combined ACL and MM lesions presented similar distribution of knee extensor and flexor IMC irregularities, which was not present in knees with isolated MM lesions. A possible association between specific knee pathologies and IMC irregularities was identified (all p<0.05). In conclusion, different knee pathologies may be associated with different qualitative IMCs, which could be used as an additional presentation tool in clinical settings.

Femoroacetabular impingement syndrome is associated with alterations in hindfoot mechanics: A three-dimensional gait analysis study.

BACKGROUND: Gait analysis studies in patients with femoroacetabular impingement syndrome focused until today on alterations in pelvic and hip mechanics, but distal articulations in this syndrome were not explored. Viewing the inter-relationships between foot and hip mechanics and the importance of the subtalar joint in load attenuation at heel strike and during forward propulsion thereafter, alterations in hindfoot mechanics in this syndrome may have clinical significance. METHODS: Three-dimensional gait kinematics were explored with emphasis on hindfoot mechanics in a group of 15 men with cam-type femoroacetabular impingement and compared to 15 healthy men. FINDINGS: Subjects with femoroacetabular impingement had decreased pelvic internal rotation (effect size=0.70) and hip abduction (effect size=0.86) at heel strike, and increased sagittal pelvic range of motion during the stance (effect size=0.81), compared to controls. At the hindfoot level, subjects with femoroacetabular impingement had inverted position at heel strike compared to neutral position in controls (effect size=0.89), and reduced maximum hindfoot eversion during the stance (effect size=0.72). Range of motion from heel strike to maximum eversion was not different between the groups (effect size=0.21). INTERPRETATION: Young adult men with cam-type femoroacetabular impingement syndrome present excessively inverted hindfoot at the moment of heel strike and reduction in maximum eversion during the stance phase. Viewing the deleterious effects of hindfoot malalignment on load attenuation during the stance, custom-designed insoles may be a consideration in this population and this should be investigated further.

Plantar Pressure Anomalies After Open Reduction With Internal Fixation of High-Grade Calcaneal Fractures.

BACKGROUND: Plantar pressure abnormalities after open reduction with internal fixation (ORIF) of intra-articular calcaneal fractures have been observed previously, but high-grade fractures were not selectively investigated and follow-up times were shorter than 2 years. The purpose of this study was to characterize plantar pressure anomalies in patients with exclusively high-grade calcaneal fractures after ORIF with a minimum 2 years of follow-up, and to test the association between plantar pressure distribution and the clinical outcome. METHODS: The orthopaedic registry was reviewed to identify patients with isolated high-grade calcaneal fractures (Sanders types III-IV) who were operated on and had a minimum 2 years of follow-up. Sixteen patients were evaluated. Mean age was 47 years and follow-up was between 2 and 6 years. The Pedar-Mobile system was used to measure 3 loading and 3 temporal variables and compare these between the operated and the uninjured limbs. RESULTS: Mean American Orthopaedic Foot and Ankle Society (AOFAS) score was 76 ± 7 at latest follow-up. Bohler's angle was 5 ± 8 degrees before surgery and 25 ± 7 degrees at latest follow-up. Stance was shorter in operated limbs (P = .001). Timing of the peak of pressure was delayed in operated limbs under the hallux and the second toe (P ≤ .03). Peak pressure, force time integral, and pressure time integral were increased under the lateral midfoot (P ≤ .03) and decreased under the second metatarsal (P ≤ .03). Force time integral was decreased under the first metatarsal (P = .02) and under the hallux and the lateral toes (P ≤ .05). Increased loading under the lateral midfoot and decreased loading under the lateral toes were correlated with poorer clinical outcome (r = -.53, P < .05, and r = .63, P < .01, respectively). CONCLUSIONS: Side-to-side plantar pressure mismatch persisted at more than 2 years after ORIF of high-grade calcaneal fractures performed via lateral approach, despite improvement of Bohler's angle. This was characterized by shortened stance phase, delayed timing of peak of pressure under the hallux and second toe, lateral load shift at the midfoot, and decreased toe pressures in operated limbs. Since loading abnormalities were correlated with the clinical outcome, modifications in treatment strategy that can improve foot loading may be desirable in these cases. LEVEL OF EVIDENCE: Level III, case control.

Analysis of foot and ankle kinematics after operative reduction of high-grade intra-articular fractures of the calcaneus.

BACKGROUND: High-grade calcaneal fractures represent a complex injury, with limited data to support the advisability of open reduction. Restoration of foot and ankle kinematics during walking, which has been previously shown to be significantly limited after nonoperative treatment, has never been studied after the operation. This study was designed to address this lack of information to assess the advisability of the operation in this respect. METHODS: Twenty patients with a minimum of 2 years after Open Reduction Internal Fixation (ORIF) for high-grade fractures were evaluated with a computerized gait analysis system, in addition to the radiographic assessment and functional questionnaires. Foot and ankle kinematic variables in the operated limbs were compared with contralateral limbs and with matched healthy control individuals. RESULTS: The kinematical gait analysis demonstrated recreation of normal ankle motions in operated patients. Subtalar motion demonstrated relative symmetry between operated and contralateral limbs, but it was still significantly limited compared with healthy controls. Bohler angle was between 15° and 35°. Functional questionnaires and rate of postoperative complications supported the generalizability of our operated group compared with previous literature assessing similar injuries. CONCLUSIONS: In high-grade calcaneal fractures, when recreation of gross calcaneal anatomy is obtained during the operation, walking ankle motion is recreated as well. However, subtalar motions, although recreated to a certain extent, still demonstrate limitations when compared with noninjured individuals. These results support the advisability of the operation in these complex injuries, but they demonstrate that subtalar motion is not completely normalized despite a favorable anatomic outcome.

Analysis of foot structure in athletes sustaining proximal fifth metatarsal stress fracture.

BACKGROUND: In the past, several studies provided anecdotal descriptions of high-arched feet in individuals sustaining proximal fifth metatarsal stress fractures. This relationship has never been supported by scientific evidence. Our objective was to examine whether athletes who sustained this injury had an exceptional static foot structure or dynamic loading pattern. MATERIALS AND METHODS: Ten injured professional soccer players who regained full professional activity following a unilateral proximal fifth metatarsal stress fracture and ten control soccer players were examined. Independent variables included static evaluation of foot and arch structure, followed by dynamic plantar foot pressure evaluation. Each variable was compared between injured, contra-lateral uninjured, and control feet. RESULTS: Static measurements of foot and arch structure did not reveal differences among the groups. However, plantar pressure evaluation revealed relative unloading of the fourth metatarsal in injured and uninjured limbs of injured athletes compared with control, while the fifth metatarsal revealed pressure reduction only in the injured limbs of injured athletes. CONCLUSION: Athletes who sustained proximal fifth metatarsal stress fracture were not characterized by an exceptional static foot structure. Dynamically, lateral metatarsal unloading during stance may either play a role in the pathogenesis of the injury, or alternately represent an adaptive process. CLINICAL RELEVANCE: Footwear fabrication for previously injured athletes should not categorically address cushioning properties designed for high-arch feet, but rather focus on individual dynamic evaluation of forefoot loading, with less attention applied to static foot and arch characteristics.

The effect of long-term beta-adrenergic receptor blockade on the oxygen delivery and extraction relationship in patients with coronary artery disease.

PURPOSE: We evaluated the effects of long-term beta-blocker treatment on the balance between oxygen delivery and extraction at peak oxygen uptake (VO2) and at target heart rate training (anaerobic threshold). METHODS: Fifteen patients with coronary artery disease performed paired peak cardiopulmonary and submaximal exercise tests on a cycle ergometer with and without atenolol treatment. Thirty minutes following the submaximal tests, participants pedaled 10 minutes at a workload corresponding to that of the anaerobic threshold attained. Arterial oxygen was defined from echocardiography and venous oxygen content. RESULTS: At rest, stroke volume, heart rate, and cardiac output were lower (P < .05), whereas arteriovenous oxygen difference [(a - v)O2] was higher with the use of atenolol (P < .05). At peak exercise, heart rate, lactate, and systolic blood pressure were lower (P < .05), whereas (a - v)O2 was higher (P < .05) with the use of atenolol. At anaerobic threshold, stroke volume, heart rate, cardiac output, and systolic blood pressure were lower (P < .05), whereas (a - v)O2 was higher (P < .05) with the use of atenolol. Absolute VO2 and workload during maximal (P = .67 and P = .49, respectively) and submaximal (P = .13 and P = .44, respectively) exercises were similar between conditions. CONCLUSIONS: Results demonstrate that atenolol treatment in patients with coronary artery disease does not alter VO2 and workload at the anaerobic threshold and peak exercise because of an increase in oxygen extraction and stroke volume in the face of reduced heart rate. These findings indicate that with long-term beta-adrenergic receptor blockade, there is interplay between oxygen delivery and extraction, suggesting a link between cardiac hemodynamic responses and skeletal muscle metabolic adaptations.

Left ventricular contractility in response to upright isometric exercise in heart transplant recipients and healthy men.

PURPOSE: We evaluated left ventricular contractility during upright isometric exercise, in heart transplant recipients (HTRs) and in healthy controls, using ejection fraction and end-systolic pressure/volume ratio indexes. METHODS: Fifteen healthy men (40 +/- 13 years) and 10 HTRs (42 +/- 12 years) underwent dead lift (DL) test at 30% of maximal effort for 3 minutes. Echocardiographic variables were measured during the final 45 seconds. RESULTS: During DL test, HTRs were significantly different (P < .01) from controls in all parameters except end-diastolic volume. DL test had lower mean values of ejection fraction (49.9% +/- 8.3% vs 67.0% +/- 4.3%, respectively) and left ventricular end-systolic pressure/volume ratio (3.5 +/- 0.7 vs 5.5 +/- 1.2, respectively) whereas higher values of end-systolic volume (51.0 +/- 9.4 mL vs 34.1 +/- 5.3 mL, respectively). Importantly, an intergroup effect was found in end-systolic pressure/volume ratio, further signifying differential response of HTRs. End-systolic pressure/volume ratio increased consistently (P < .001) in both groups, whereas the overall main effect of ejection fraction response was not significant. CONCLUSIONS: Left ventricular function during upright isometric exercise displays differential pattern of response in HTRs in comparison with healthy controls. However, cardiac contractility in HTRs remained stable at peak systolic blood pressure produced by the isometric DL exercise. Results suggest that both ejection fraction and end-systolic pressure/volume ratio indexes can be used for assessment of ventricular function in patients after heart transplantation.

The role of foot pronation in the development of femoral and tibial stress fractures: a prospective biomechanical study.

OBJECTIVE: To examine whether dynamic parameters of foot pronation are risk factors for the development of stress fractures of the femur and tibia. DESIGN: Observational prospective study. SETTING: Infantry basic training course. PARTICIPANTS: 473 recruits evaluated for stress fractures of the femur and tibia every 2 weeks during 14 weeks of infantry basic training. The final analysis included 405 recruits. ASSESSMENT OF RISK FACTORS: Two weeks before commencement of training, the recruits were evaluated during treadmill walking for their subtalar joint kinematics. Five independent variables were measured bilaterally: maximal pronation angle during the stance, pronation range of motion, time from heel strike to maximum pronation, pronation mean angular velocity, and time to maximum pronation as a percent of the total stance time. MAIN OUTCOME MEASUREMENTS: Stress fractures of the femur and tibia. These were considered positive only when proven by imaging. RESULTS: Ten percent of the participants were diagnosed with stress fractures of the femur and tibia. Recruits with longer duration of foot pronation had reduced odds ratio to develop this injury. CONCLUSIONS AND CLINICAL RELEVANCE: Longer duration of foot pronation may have a protective effect from stress fractures of the femur and tibia. This finding may promote the understanding of stress fracture pathomechanism, assist in the identification of subjects with increased risk who need augmented monitoring throughout training, and assist in future planning of impact reducing aids.

What maintains energy supply at peak aerobic exercise in trained and untrained older men?

BACKGROUND: Aging-related changes occur mainly in the cardiopulmonary system and skeletal muscles, bringing about a reduction in physical performance. Consequently, maximal oxygen uptake (VO(2)max) decreases. OBJECTIVES: The current study investigated exercise oxygen utilization during maximal aerobic exercise in trained and untrained elderly. METHODS: Fifteen trained (59.3 +/- 1.1 years) and 15 untrained (60.1 +/- 1.1 years) elderly underwent a peak cardiopulmonary exercise test on a bicycle ergometer. Arterial O(2 )was defined from echocardiograph and venous oxygen content. RESULTS: At rest, trained compared to untrained elderly had significantly (p < 0.05) higher values of end diastolic volume (108.1 +/- 5.8 and 100.7 +/- 6.2 ml, respectively) and stroke volume (68.1 +/- 4.3 and 57.3 +/- 6.5 ml, respectively), while heart rate (68.7 +/- 9.3 and 81.3 +/- 8.2 beats . min(-1), respectively), and mean arterial blood pressure (90.6 +/- 6.9 and 95.4 +/- 7.2 mm Hg, respectively) were significantly lower. At peak aerobic test, the trained elderly, compared to the untrained subjects, achieved significantly (p < 0.05) higher values of end diastolic volume (156.1 +/- 8.2 and 134.1 +/- 7.6 ml, respectively), stroke volume (123.0 +/- 7.9 and 96.0 +/- 4.8 ml, respectively), cardiac output (20.2 +/- 1.5 and 15.0 +/- 1.3 liters.min(-1), respectively) and oxygen uptake (42.1 +/- 2.1 and 31.1 +/- 2.4 ml.kg(-1).min(-1), respectively), while diastolic blood pressure (70.3 +/- 5.6 and 77.5 +/- 4.2 mm Hg, respectively) and total peripheral resistance [4.3 +/- 0.8 and 5.9 +/- 1.41 (dyn.s(-1).cm(-5)).10(-1), respectively], were significantly (p < 0.05) lower. CONCLUSIONS: The present study suggests that the differences between trained and untrained elderly in absolute oxygen uptake of the working muscles and peak power output at maximal exercise test are due to physical activity status. The higher aerobic capacity in the trained elderly is related to increased cardiovascular function and to a lesser extent to increased muscle mitochondria concentration and capillarity. Although untrained elderly have reduced maximal oxygen uptake at peak aerobic exercise, intrinsic regulation of mitochondrial function does not seem to be significantly altered because of aging associated physical inactivity. Therefore, untrained elderly can partially compensate for their lower cardiac output by increasing oxygen extraction to levels comparable with those of trained elderly.

What maintains the metabolic cost at maximal exercise in heart transplant recipients and coronary artery disease patients?

BACKGROUND: In this study we assess the influence of disease status on hemodynamic and cardiac output values, as measured by oxygen utilization at peak aerobic exercise, in heart transplant recipients (HTRs) and coronary artery disease patients (CAD). METHODS: Fifteen CAD patients and 13 HTRs (40.2 +/- 12.6 and 41.7 +/- 11.7 years, respectively) underwent a peak cardiopulmonary exercise test on bicycle ergometry. Arterial oxygen was defined on the basis of echocardiography and venous oxygen content. RESULTS: At rest, except for cardiac output, oxygen uptake and lactate levels, all variables were significantly (p < 0.01) different between groups. At peak exercise, compared with HTRs, CAD patients had significantly (p < 0.0001) higher values for cardiac output (12.4 +/- 0.8 and 20.2 +/- 1.7 liters/min, respectively), stroke volume (87.3 +/- 5.4 and 129.3 +/- 9.7 ml, respectively) and oxygen uptake (22.7 +/- 3.6 and 29.7 +/- 2.7 ml/kg/min, respectively) (p < 0.01), whereas (a - v)O2 was significantly lower (127.0 +/- 4.3 and 141.9 +/- 6.4 O2 ml/liter, respectively; p < 0.0001). CONCLUSIONS: The differences in oxygen utilization at peak exercise may be attributed to differences in energy metabolism, namely higher oxygen extraction in HTRs, compensating for the dramatically reduced oxygen delivery. It is further suggested that CAD patients and HTRs respond to a greater extent to maximal aerobic testing by reducing their left ventricular systolic function despite increased after-load.

Paraoxonase activity following exercise-based cardiac rehabilitation program.

PURPOSE: The effect of gender on paraoxonase activity was determined in 37 ischemic heart disease patients who underwent a 12-week aerobic exercise training program. METHODS: Paraoxonase activity was measured by its arylesterase activity (spectrophotometrically, at 250 degrees C, wavelength 270 nm). RESULTS: A 16.7% increase in paraoxonase activity was found following the 12-week exercise program. In addition, there was a significant gender effect with higher mean paraoxonase levels among women during both preexercise (20.8%) and postexercise (24.2%) testing. CONCLUSIONS: Aerobic exercise training was found to be an effective means in inducing plasma levels elevation of the antioxidative, antiatherogenic paraoxonase in patients with coronary artery disease, and particularly in female patients.

Igf-I and fgf-2 responses to wingate anaerobic test in older men.

REDUCED ACTIVITY OF THE POTENT ANABOLIC EFFECTORS: insulin-like growth factor-I (IGF-I) and fibroblast growth factor-2 (FGF-2), play a role in aging associated muscle loss. The effect of fitness level on IGF-I and FGF-2 responses to all-out anaerobic exercise in older men was studied. Twenty four healthy older males: 12 higher fit (58 ± 1y) and 12 lower fit (59 ± 1y) underwent the Wingate anaerobic test. Serum levels of IGF-I and FGF-2 were measured before, immediately after exercise, and 50 min into recovery. Immediately post exercise, the average peak power output and serum lactate were higher (p < 0.05) in the higher fit (446.0 ± 14. 9 kgm·min(-1) for mean (± SD) peak power and 12.6 ± 1.1 mml·l(-1) for lactate) compared with the lower fit individuals (284.0 ± 6.5 kgm·min(-1) and 8.5 ± 0.7 mml·l(-1), respectively). Pre-exercise IGF-I was lower and FGF-2 was higher in the higher fit (335.0 ± 54.0 ng·ml(-1) and 1.6 ± 0.1 ng·ml(-1), respectively) compared with lower fit individuals (402.0 ± 50.0 ng·ml(-1) and 1.4 ± 0.2 ng·ml(-1), respectively). Following the anaerobic exercise, in both groups, FGF-2 decreased dramatically (p < 0.05); in the higher fit individuals FGF-2 level was 0.4 ± 0.1 pg·ml(-1) compared to 0.1 ± 0.02 pg·ml(-1) in the lower fit individuals. In contrast to FGF-2, IGF-I increased transiently to levels of 405.0 ± 62.0 ng·ml(-1) in the higher fit individuals and to levels of 436 ± 57.0 ng·ml(-1) in the lower fit individuals. However, the IGF-I elevation was significant (p < 0. 05) only in the higher fit individuals. In conclusion, the present study demonstrates that during aging, fitness level can alter circulating levels of IGF-I and FGF-2. Furthermore, fitness level can affect the response of both mediators to all-out anaerobic exercise. Key pointsThe present study suggests that during aging, fitness level can alter circulating levels of IGF-I and FGF-2.Furthermore, fitness level can affect the response of both mediators to all-out anaerobic exercise.Anaerobic muscle activity is represented in many daily life activities of elderly individuals.This may have clinical implications during aging, where the declined activity of growth factors is a major determinant of the loss of muscle strength and function.

Left ventricular systolic function during treadmill walking with load carriage in adolescents.

Backpack carriage occurs in day-to-day tasks and has applications in school, physical training, recreational activities and sports. Using metabolic cart and echocardiograph, this study determined and examined the effects of two different load carriages on left ventricular function during 30 min. of treadmill walking in healthy adolescent male subjects. Seventeen males (13.1 ± 0.5 yrs.) walked on a treadmill at a speed of 4 km·h(-1), each carrying a load relative to his body mass at 333 gr·kg(-1) body weight during one session and without weight during the other session. Significant (p < 0.05) differences were noted between the 333 gr·kg(-1) body weight and the no weights with regard to: VO2 13.6 ± 1.3 and 10.5 ± 1.1 ml·kg(-1)·min(-1); heart rate: 133.2 ± 7.1 and 121.4 ± 5.6 beats·min(-1); mean arterial blood pressure; 95. 4 ± 4.3 and 87.5 ± 3.8 mmHg and systolic blood pressure 147.7 ± 7.0 and 129.8 ± 7.1 mmHg respectively. No significant differences were noted between the two exercises with regard to left ventricular function variables. This study suggests that in adolescents as in adults, the vasodilatation mechanism dominates during combined dynamic and isometric exercises. Thus, the opposing force to the left ventricular ejection is reduced which in turn does not change the left ventricular global function. In addition, the vasodilatation mechanism enables oxygen supply to the contracting muscles via aerobic energy pathways. Key PointsThis study suggests that in adolescents as in adults, the vasodilatation mechanism dominates during combined dynamic and isometric exercises.Thus, the opposing force to the left ventricular ejection is reduced which in turn does not change the left ventricular global function.In addition, the vasodilatation mechanism enables oxygen supply to the contracting muscles via aerobic energy pathways.

Left ventricular function at peak all-out anaerobic exercise in older men.

BACKGROUND: All-out anaerobic exercise may be dangerous for the older population, due to hypoxia and inappropriate blood pressure response. OBJECTIVES: This study compared and evaluated left ventricular function at peak all-out anaerobic effort in 12 well-trained older (58 +/- 1 years) and 12 young men (22 +/- 1 years). METHODS: Subjects were studied by echocardiography at peak all-out anaerobic exercise, on a cycle ergometer. RESULTS: Seven older subjects experienced ECG abnormalities. Significant (p < 0.05) differences between the older group and the young group, respectively, were noted for: cardiac output (9.8 +/- 0.9 and 15.8 +/- 0.9 l.min(-1)), left ventricular end-systolic pressure-volume ratio (4.7 +/- 0.8 and 4.4 +/- 4.9), left ventricular end-diastolic volume (104.8 +/- 6.9 and 125.7 +/- 6.2 ml), ejection fraction (67.1 +/- 6.0 and 59.8 +/- 5.5%), left ventricular end-systolic pressure volume ratio (4.4 +/- 0.4 and 4.8 +/- 0.3 ratio), and total peripheral resistance (966.0 +/- 84.0 and 660 +/- 82.8 dyn.s(-1).cm(-5)). CONCLUSIONS: Data suggest that during all-out anaerobic exercise, forces opposing ejection were not reduced enough to avoid left ventricular dysfunction and ECG abnormalities in the older subjects. This is attributed to functional changes with age in the myocardium and associated blood vessels, leading to impairment of left ventricular function and blunted inotropic and chronotropic responses to catecholamine. Therefore, an all-out anaerobic-type effort should not be given to an older subject due to the great hazardous potential.

Effect of changes in load carriage while walking on the left ventricular function in highly trained elderly subjects.

BACKGROUND: In previous studies, the effect of isometric stress on the dynamic performance of a graded exercise test in normal subjects augmented afterload and brought about changes in left ventricular function more often than did results from physical exercise. OBJECTIVE: This study used the metabolic charts and echocardiography to examine the influence of two different types of load carriage during 30 min of treadmill walking on left ventricular function, hemodynamics, and cardiovascular responses. METHODS: Fifteen elderly (age 66.1 +/- 3.5 years) aerobically well-trained male subjects (VO(2 peak) 44.2 +/- 5.0 ml x kg(-1) x min(-1)) volunteered in this study. The subjects walked on a treadmill (at a speed of 4.5 km x h(-1)), carrying a load of 20 kg during one session and a load of 30 kg during a second session. RESULTS: Following the 30-min exercise in each session, significant (p < 0.05) differences were noted between the 20-kg and the 30-kg work loads with regard to cardiac output (6.8 +/- 0.5 and 7.8 +/- 0.4 l.min(-1)), heart rate (114.0 +/- 11.0 and 126.0 +/- 10.0 beats.min(-1)), diastolic blood pressure (79.4 +/- 5.0 and 84.3 +/- 5.0 mm Hg, mean arterial blood pressure (104.0 +/- 4.0 and 109.2 +/- 3.0 mm Hg), and left ventricular contractility ratio (3.3 +/- 0.4 and 3.6 +/- 0.3). No significant differences were noted between the work loads with regard to systolic blood pressure, cardiac output, left ventricular volumes, and ejection fraction. CONCLUSIONS: This study suggests that in the highly trained elderly, the influence of the autoregulation mechanism dominates during combined dynamic and isometric exercises, thus the opposing force to the left ventricular ejection is reduced which in turn does not change left ventricular global function.

Beta-blockers, exercise, and the immune system in men with coronary artery disease.

PURPOSE: The purpose of the present study was to examine the effect of aerobic exercise training on the immune system in coronary artery disease patients treated with beta-blockers. METHODS: Twenty-five patients (46.1 +/- 2 yr) treated with atenolol, a beta-blocker agent, for 3 months before exercising were divided randomly into two groups: 15 underwent an aerobic exercise training program for 12 wk at 65-70% of their work capacity, whereas the other 10 patients served as controls. RESULTS: After training, levels of CD4 and CD8 cells were significantly (P < 0.05) higher and concomitantly the CD4/CD8 ratio decreased significantly (P < 0.05) in the exercising group compared with the control group. CONCLUSIONS: Data suggest that coronary artery disease patients exercising aerobically at 65-70% of their work capacity gain a statistically significant higher lymphocyte T cell function as compared with their untrained counterparts.