Postural Control Strategies and Balance-Related Factors in Individuals with Traumatic Transtibial Amputations.

Mechanisms behind compromised balance control in people with transtibial amputation need to be further explored, as currently little is known specifically about postural control strategies in people with traumatic transtibial amputation (tTTA). The aim of this study is to assess automatic and voluntary postural control strategies in individuals with unilateral tTTA compared to those in control subjects and to define the effect of balance-related factors on these strategies. Automatic posture reactions and volitional motion toward given direction using standardized posturographic protocols (NeuroCom) of the Motor Control Test (MCT) and Limits of Stability (LOS) were assessed in eighteen participants with tTTA and eighteen age-matched controls. Compared to the controls, the participants with tTTA bore less weight on the prosthetic leg (p < 0.001) during the MCT and had reduced inclination toward the prosthetic leg (p < 0.001) within the LOS. In the tTTA group, the weight-bearing symmetry and the inclination toward the prosthetic leg (p < 0.05) was positively correlated with prosthesis use duration (p < 0.05). The current study indicates that decreased utilization of the prosthetic leg in tTTAs represents adaptive postural control strategy, but as prosthesis use duration increased, the engagement of the prosthetic leg improved.

Evaluation of Explosive Power Performance in Ski Jumpers and Nordic Combined Competitive Athletes: A 19-Year Study.

Between 1992 and 2010, a total of 334 males participated in this study that assessed the differences and relationships between anthropometric variables and lower limb muscle strength in young and adult ski jumpers (n = 207) and Nordic combined (NC, n = 127) athletes. All athletes completed a maximal vertical jump from an in-run position and a maximal relative isometric force (MRIF) of the knee extensor measurement in a laboratory setting. The body mass index (BMI) in young competitors was lower than in adult groups (NC: p < 0.001; ski jumping [SJ]: p < 0.001). Similarly, the MRIF in both limbs was lower for both disciplines in the groups of young competitors. The vertical jump height (VJH) was lower for young competitors than for adults (NC: p ≤ 0.05; SJ: p < 0.001). When comparing SJ and NC athletes, BMI was lower in SJ athletes. In addition, the adult SJ competitors exhibited greater values of bilateral MRIF (p ≤ 0.05) and VJH (p < 0.01). There was a strong positive correlation in MRIF between the left and right lower limbs (p < 0.001) for all groups of SJ and NC athletes; therefore, it was determined to be sufficient to measure the MRIF on a single limb. Application of the new training methods (e.g., less emphasis on maximum resistance exercises) resulted in improved explosive power in ski jumpers even at lower-body weights. These changes are in accordance with the change in ski jump techniques.

Ski-jumpers' performance in a laboratory setting: a 29-year longitudinal study.

This study assesses the longitudinal changes in anthropometric and motor parameters of ski jumpers. Male ski jumpers (n = 329) at various competitive levels participated in this study. These competitors were divided into two groups by age (18 years and younger, and over 18 years), and then divided into seven even intervals within those groups. Basic anthropometric parameters, maximal relative isometric knee extensor force, reaction time, knee extension time, and vertical jump height were measured. The conditions, instruments, and systems of measurement were consistent throughout the study. A reduced body mass index (BMI) in the adult jumpers was significant (P < .01) in the first three (1982-1993) and in the last three (1998-2010) intervals. Adults had an increase of maximal relative isometric knee extensor force (P < .01) in the last three intervals (1998-2010). They had greater maximal relative isometric knee extensor force (with exception of the first interval, 1982-1985) and vertical jump height than younger competitors (P < .01). Both young and adult jumpers exhibited the increase of strength and power in the lower limbs and a decrease in BMI during the whole observed period.

Limits of stability in persons with transtibial amputation with respect to prosthetic alignment alterations.

OBJECTIVES: To evaluate the limits of stability (LOS) in persons with transtibial amputation (TTA), and to determine the effects of prosthetic alignment alterations on motor control strategies. DESIGN: Before-and-after trial. SETTING: A kinesiology laboratory at a university hospital. PARTICIPANTS: Male patients with TTA (n=10) and controls (n=17). INTERVENTIONS: Prosthetic alignment. MAIN OUTCOME MEASURES: For the LOS test, the maximum excursion, endpoint excursion, direction control, movement velocity, and reaction time with inclination in the forward direction, toward the amputated leg/right leg, and in the backward direction, and toward the nonamputated leg/left leg. Measurements were performed using the following 5 prosthetic alignments: the optimal alignment, with the prosthesis shorter by 1cm, with the prosthesis longer by 1cm, and with the prosthetic foot in 5° of extra plantar flexion and 5° of extra dorsiflexion. RESULTS: Compared with the control group, maximum excursion and direction control were lower (P<.05) in patients with TTA with backward body inclination for all tested prosthetic alignments. Direction control in backward inclination was reduced (P<.05) compared with other tested directions for all assessed prosthetic alignments. Differences between the tested alignments were not significant in any of the tested directions. CONCLUSIONS: Patients with TTA have decreased voluntary body inclination backward within the LOS for all tested prosthetic alignments. Compared with controls, changes in prosthetic foot settings by means of rotation in the sagittal plane had a larger impact on movement strategy in patients with TTA than did changes to the length of the prosthesis.

Kinetic analysis of ski turns based on measured ground reaction forces.

The objective of this study was to devise a method of kinetic analysis of the ground reaction force that enables the durations and magnitudes of forces acting during the individual phases of ski turns to be described exactly. The method is based on a theoretical analysis of physical forces acting during the ski turn. Two elementary phases were defined: (1) preparing to turn (initiation) and (2) actual turning, during which the center of gravity of the skier-ski system moves along a curvilinear trajectory (steering). The starting point of the turn analysis is a dynamometric record of the resultant acting ground reaction force applied perpendicularly on the ski surface. The method was applied to six expert skiers. They completed a slalom course comprising five gates arranged on the fall line of a 26° slope at a competition speed using symmetrical carving turns (30 evaluated turns). A dynamometric measurement system was placed on the carving skis (168 cm long, radius 16 m, data were recorded at 100 Hz). MATLAB procedures were used to evaluate eight variables during each turn: five time variables and three force variables. Comparison of the turn analysis results between individuals showed that the method is useful for answering various research questions associated with ski turns.

Gender and Age Related Differences in Leg Stiffness and Reactive Strength in Adolescent Team Sports Players.

The aim of the present study was to identify potential gender differences in leg stiffness and reactive strength during hopping tasks in 13 to16-year old team sports players. Reactive strength index (RSI) and leg stiffness were obtained in two consecutive seasons from 51 girls (U14: n = 31, U16: n = 20) and 65 boys (U14: n = 32, U16: n = 33). A significant main effect on absolute (U14: p = 0.022, η2= 0.084; U16: p < 0.001, η2= 0.224) and relative leg stiffness (U14 p<0.001; η2= 0.195; U16; p = 0.008, η2= 0.128) for gender was found in both groups with values higher in boys than in girls. For absolute and relative stiffness gender differences in the U14 group were significant in the 1st year only (p=0.027 and p=0.001), and for the U16s in the 2nd year only (p < 0.001 and p = 0.022). For RSI, a significant main effect for gender was observed in the U16 group only (p < 0.001 η2= 0.429) with values significantly higher in boys than in girls in both years of measurement (p = 0.001; p < 0.001). Results of this study support previous limited findings, mostly related to non-athletes, suggesting lower stretch-shortening cycle capability in adolescence female compared to male, however our data only partly supports the theory that quality of neuromuscular functions increases with age until post puberty.

Electrical stimulation of hyoid muscles in post-stroke dysphagia.

AIMS: The purpose of this study was to evaluate swallowing changes in post-stroke patients with dysphagia after four weeks of suprahyoid muscles electrical stimulation. METHODS: This was a prospective randomized study of early stage stroke patients with dysphagia. Electrical stimulation of suprahyoid muscles was given to a group of 54 patients (26 men, average age 70 years) for 20 minutes a day, 5 days a week. Standard orofacial rehabilitation without electrical stimulation was carried out on a control group of 54 patients (31 men, average age 69 years). Swallowing was evaluated at the beginning of the study and at the end, by videofluoroscopy - measuring the time for oral and pharyngeal phases. RESULTS: The difference in duration of oral transit time (OTT) after the therapy between the study group (average: 0.55 ± 0.01) and the control group (average: 0.29 ± 0.03) was statistically significant (P=0.01). Difference in duration of the pharyngeal transit time (PTT) after the therapy between the study group (average: 0.37 ± 0.02) and control group (average: 0.15 ± 0.02) was also statistically significant (P=0.009). CONCLUSION: Electrical stimulation of suprahyoid muscles significantly reduced the duration of the oral and pharyngeal phases: in the post-stroke patients with dysphagia used in this study. The result is improved swallowing. This is a recently recommended approach and your study confirms its efficacy.

Central facial paresis and its impact on mimicry, psyche and quality of life in patients after stroke.

AIM: Using functional scales and face video analysis, changes in central facial paresis are monitored in patients with stroke after orofacial therapy and correlations between changes in mimicry, mental function and overall quality of life of patients after stroke are made. MATERIALS AND METHODS: A prospective randomized study of patients after stroke with facial paresis. The functional status of the experimental group of 50 cases with orofacial regulation therapy and 49 control cases without mimicry therapy is observed after four weeks of rehabilitation. RESULTS: Changes in mimicry functions evaluated by the House-Brackmann Grading System (HBGS) clinical range and using 2D video analysis of the distance between the paretic corner of the mouth and earlobe at rest and during smiling were statistically better in the experimental group than in controls. Changes in mental function - depression using Beck Depression Inventory and changes in the quality of life using Bartle index and modified Rankin score (scale) were significantly greater in the experimental group. There was a very close relationship between the changes in mimicry, mental state and overall quality of life according to the Spearman correlative coefficient. CONCLUSION: Orofacial rehabilitation therapy for patients with paresis after stroke has a significant influence on the adjustment of mimicry, mental functions and overall quality of life after 4 weeks of treatment.

Kinematic Chains in Ski Jumping In-run Posture.

The concept of kinematic chains has been systematically applied to biological systems since the 1950s. The course of a ski jump can be characterized as a change between closed and open kinematic chains. The purpose of this study was to determine a relationship between adjacent segments within the ski jumper's body's kinematic chain during the in-run phase of the ski jump. The in-run positions of 267 elite male ski jumpers who participated in the FIS World Cup events in Innsbruck, Austria, between 1992 and 2001 were analyzed (656 jumps). Two-dimensional (2-D) kinematic data were collected from the bodies of the subjects. Relationships between adjacent segments of the kinematic chain in the ski jumper's body at the in-run position are greater nearer the chain's ground contact. The coefficient of determination between the ankle and knee joint angles is 0.67. Changes in the segments' positions in the kinematic chain of the ski jumper's body are stable during longitudinal assessment. Changes in shank and thigh positions, in the sense of increase or decrease, are the same.

Variability of kinetic variables during gait in unilateral transtibial amputees.

BACKGROUND: Prosthetic gait increases demands on stability. Some variability measures can be used to investigate the stability of movement for prosthetic feet. OBJECTIVES: The purpose of this study was to determine the influence of the prosthetic foot on ground reaction force variability for transtibial amputee gait. STUDY DESIGN: Comparative analysis. METHODS: Eleven male unilateral transtibial amputees participated in this study. Each subject walked at self-selected speed with both conventional (SACH) and energy storing (Sureflex) feet. Time and ground reaction force variables and their coefficients of variation were calculated for each foot type and limb. RESULTS: Mediolateral force variables had high variability for all conditions. The Sureflex had a larger variability than the SACH foot for the braking peak (p < 0.05), which may have been caused by gait instability after the heel strike. There were significant differences between intact and prosthetic limbs in total loading (force impulses) with the SACH foot (p < 0.05). CONCLUSIONS: The prosthetic foot and alignment issues related to the foot influence GRF variability. During the braking phase the SACH foot is characterized by higher variability in mediolateral direction and Sureflex by higher variability in anterior-posterior direction. CLINICAL RELEVANCE: Differences in variability in ground reaction force variables can represent a person's stability. Observing variability can contribute to better understanding of critical events in gait cycle with the use of various prosthetic feet.

Facial paresis after stroke and its impact on patients' facial movement and mental status.

OBJECTIVE: The aims of this study were: (i) to monitor changes in central facial paresis in patients with stroke after orofacial therapy, using functional scales and video analysis of the face; and (ii) to investigate correlations between changes in facial movement and mental function of patients after stroke. METHODS: A prospective blind randomized study of patients after stroke with facial paresis. The functional status of the experimental group of 50 cases treated with regulation orofacial therapy was compared with 49 control cases after 4 weeks of rehabilitation. RESULTS: There were changes in facial movement, evaluated with the House-Brackmann Grading System (HBDS), clinical range and two-dimensional video analysis of the distance between the paretic corner of the mouth and earlobe at rest and during smiling, were measured. Facial movement was found to be significantly better in the experimental group after orofacial therapy compared with the control group. Changes in mental status (depression observed using the Beck Depression Inventory (BDI-II) were significantly greater in the experimental group. There was a close correlation between the changes in facial movement and mental status according to Spearman's correlation coefficient. CONCLUSION: Orofacial therapy has a significant effect after 4 weeks of treatment on facial movement and mental state in patients with stroke. Based on the results in our study we can say that the improvements are a significantly better in the experimental group (Difference value) in the parameters HBGS, distance between the corner of the mouth and earlobe and BDI-II.

Evaluation of postural asymmetry and gross joint mobility in elite female volleyball athletes.

The purpose of the study was to evaluate marked postural asymmetry and gross joint mobility in elite female volleyball athletes. Sixty-two Czech and Slovak elite female volleyball athletes (age 20.7±2.03 years, body mass 71.1±6.18 kg, body height 1.804±.0618 m, BMI 21.8±1.78) were examined by an experienced rehabilitation physician. The set of tests included the frontal posture gross examination, the forward bending test from the standing position and the deep squat test. The spiking hand and the presence of any lower extremity injury were estimated by interview. The proportion test, Mann-Whitney test and t-test were used to evaluate statistical significance (p<0.05). Fifty subjects (80.6%) exhibited "typical" frontal plane posture in which the acromion, scapula and the iliac crest were in a higher position on the left side than on the right, significantly more frequently than all the other patterns (proportion test, p<0.0001). Ninety-eight percent of the subjects with the "LLL pattern" preferred the right arm for spiking (proportion test, p<0.0001). Forty-one subjects (66%) exhibited hypermobility in the forward bending test, significantly more frequently than twenty-one subjects (34%) with normal results (proportion test, p=0.0003). Thirty-four subjects (55%) did not succeed in the deep squat test and hypermobility in the forward bending test paradoxically prevailed in them significantly (proportion test, p=0.004). Restriction in the deep squat test was not linked to obesity, age (t-test, p=0.081) nor knee (proportion test, p=0.85) and ankle injury (Mann-Whitney test, p=0.36) in the past. Significant prevalence of hypermobility in the forward bending test was not surprising because of general body composition and the performance of regular stretching exercises in elite female volleyball athletes. On the other hand, surprisingly, more than half of the subjects did not succeed in the deep squat test. The cause of poor results in the deep squat test could be due to the tightness of the soleus muscle suffering from chronic overloading and/or an inappropriate stretching methods. An inappropriate and/or insufficient compensatory exercise and stretching method or system could be the cause of their marked postural asymmetry as well. A detailed examination of posture and muscle imbalance performed by an experienced physician or physiotherapist as well as individually tailored compensatory exercises and a stretching system can be strongly recommended to all elite athletes, not only to volleyball players.

Kinematic characteristics of the ski jump inrun: a 10-year longitudinal study.

The athlete's inrun position affects the outcome for take-off in ski jumping. The purpose of this study was to examine the kinematic parameters between skiers' adjacent body segments during their first straight path of the inrun. Elite ski jumpers participated in the study at the World Cup events in Innsbruck, Austria, during the years 1992 through 2001. A video image was taken at a right angle to the tracks of the K-110 (meter) jumping hill. Kinematic data were collected from the lower extremities and trunk of the athletes. Findings indicated that jumpers had diminished ankle and knee joint angles and increased trunk and hip angles over the 10 years. In recent years, the best athletes achieved a further length of their jumps, while they experienced slower inrun average velocity. These results are perhaps explained by several possible contributing factors, such as new technique of the jumper's body kinematics, advancements in equipment technology, and somatotype of the jumpers.

Functional categorization of the individual morphology of the scapula.

The morphologic variations of the shoulder blade have not yet been evaluated in clinical medicine. We observed that subjects with less standard shapes of the shoulder blade often suffer from musculo-skeletal shoulder syndromes with concurrent intrinsic impingement syndromes or, more precisely, partial-thickness rotator cuff tears. This experience became a basis for an experiment, in which we categorized individual phenotypes of the shoulder blade. A clinically useful finding of the presented study is a tool for predicting patients at risk for manifestations of impingement syndrome and also for prediction of easy or complicated restoration of neuromuscular stabilization of the shoulder. Lower functional potential of the external rotator muscles of the shoulder is in close relation to the individual shape of the shoulder blade, for the most part with the cranio-caudal dimension of the infraspinous fossa.

An assessment of the pressure distribution exerted by a rider on the back of a horse during hippotherapy.

Hippotherapy employs locomotion impulses that are emitted from the back of a horse while the horse is walking. These impulses stimulate the rider's postural reflex mechanisms, resulting in training of balance and coordination. The aim of the present study was to assess the changes in magnitude and distribution of the contact pressure between the rider and the horse during a series of hippotherapy lessons. The monitored group, consisting of four healthy women (mean age 22.75 years, mean body weight 59.75 kg, mean height 167.25 cm) without any previous horse riding experience, received five 20 minute-lessons lessons in a three-week period. Hippotherapy was given on a 15-year-old thoroughbred mare. An elastic pad (Novel Pliance System, 30 Hz, 224 sensors) was used for pressure magnitude evaluation. The maximum pressure value was increased (p<.05) in the event of a second measurement (5th lesson). The pressure exerted on the rider upon contact of the rear limbs was higher than upon contact of the front limbs (p<.01). The size of the center of pressure (COP) deviations in the anteroposterior direction reduced (p<.05) with the number of lessons received. With the growing experience of the participant, an increase in pressure occurred on contact of her body and the horse's back as well as in the stability of the COP movement.

The choice of on- or off-pump coronary bypass grafting--a surgeon's dilemma.

BACKGROUND: Off-pump coronary bypass grafting (OPCAB) is a routine method of heart revascularization. This study was designed to compare the results of OPCAB and ONCAB performed by a single surgeon at our institution over a 3-year period. METHODS: The study enrolled 345 patients undergoing elective myocardial revascularization procedures, of which 173 (50.1%) were OPCAB and 172 (49.9 %) were ONCAB. The postoperative outcomes of both groups were analyzed, retrospectively. RESULTS: The mean number of grafts was significantly lower in the OPCAB group (2.9) than in the ONCAB group (3.7). There were no postoperative myocardial infarctions or hospital deaths in any of the patients. The postoperative total blood loss was significantly higher in the ONCAB group. The frequencies of postoperative confused states, strokes, postoperative transfusions, reoperations for bleeding, and atrial fibrillation, and the durations of intubation, ICU stay, and hospital stay did not differ significantly between the two groups. CONCLUSIONS: The OPCAB procedures are safe and provide good clinical outcomes, similar to those of ONCAB operations. The outcomes of this study favor neither of the compared techniques.