Denna bok vill inspirera, motivera och ge konkreta tips och råd så att den som är protesbärare ska kunna leva ett fysiskt aktivt liv.I boken möter du personer som delar med sig av sina egna erfarenheter och som gärna tipsar om vilka fysiska aktiviteter de har fastnat för och vad denna träning innebär för dem. En viktig förutsättning för att komma igång med ett fysiskt aktivt liv är att bygga upp grundstyrka och balans. En stor del av boken ägnas därför åt ett träningsprogram med en mängd övningar, illustrerade med bilder. Träningsprogrammet är skapat av Lee Nolan.
BACKGROUND: Gait-lines, or the co-ordinates of the progression of the point of application of the vertical ground reaction force, are a commonly reported parameter in most in-sole measuring systems. However, little is known about what is considered a "normal" or "abnormal" gait-line pattern or level of asymmetry. Furthermore, no reference databases on healthy young populations are available for this parameter. Thus the aim of this study is to provide such reference data in order to allow this tool to be better used in gait analysis. METHODS: Vertical ground reaction force data during several continuous gait cycles were collected using a Computer Dyno Graphy in-sole system(R) for 77 healthy young able-bodied subjects. A curve (termed gait-line) was obtained from the co-ordinates of the progression of the point of application of the force. An Asymmetry Coefficient Curve (AsC) was calculated between the mean gait-lines for the left and right foot for each subject. AsC limits of +/- 1.96 and 3 standard deviations (SD) from the mean were then calculated. Gait-line data from 5 individual subjects displaying pathological gait due to disorders relating to the discopathy of the lumbar spine (three with considerable plantarflexor weakness, two with considerable dorsiflexor weakness) were compared to the AsC results from the able-bodied group. RESULTS: The +/- 1.96 SD limit suggested that non-pathological gait falls within 12-16% asymmetry for gait-lines. Those exhibiting pathological gait fell outside both the +/- 1.96 and +/- 3SD limits at several points during stance. The subjects exhibiting considerable plantarflexor weakness all fell outside the +/- 1.96SD limit from 30-50% of foot length to toe-off while those exhibiting considerable dorsiflexor weakness fell outside the +/- 1.96SD limit between initial contact to 25-40% of foot length, and then surpassed the +/- 3SD limit after 55-80% of foot length. CONCLUSION: This analysis of gait-line asymmetry provides a reference database for young, healthy able-bodied subject populations for both further research and clinical gait analysis. This information is used to suggest non-pathological gait-line asymmetry pattern limits, and limits where detailed case analysis is warranted.
To explore the hypothesis that toe-walking offers certain advantages for people with upper motor neuron related impairments, the authors performed biomechanical comparisons of toe- vs. heel-toe walking in non-disabled subjects. Using traditional joint biomechanical analysis, the authors showed that toe-walking is associated with less net peak torque and power at the ankle and knee implying that less distal strength is needed to toe-walk. They also found, utilizing linear power analysis, that the lower limb can deliver power to the upper-body as effectively in toe-walking as in heel-toe walking
Older adults demonstrate increased amounts of postural sway, which may ultimately lead to falls. The mechanisms contributing to age-related increases in postural sway and falls in the elderly remain unclear. In an effort to understand age-related changes in posture control, we assessed foot center-of-pressure (COP) displacements and electromyographic data from the tibialis anterior, soleus, vastus lateralis, and biceps femoris collected simultaneously during quiet-standing trials from elderly fallers, elderly non-fallers, and healthy young subjects. Both traditional measures of COP displacements and stabilogram-diffusion analysis were used to characterize the postural sway of each group. Regression analyses were used to assess the relationship between the COP measures and muscle activity. Elderly fallers demonstrated significantly greater amounts of sway in the anteroposterior (AP) direction and greater muscle activity during quiet standing compared with the young subjects, while elderly non-fallers demonstrated significantly greater muscle activation and co-activation compared with the young subjects. No significant differences were found between elderly fallers and elderly non-fallers in measures of postural sway or muscle activity. However, greater postural sway in both the AP and mediolateral (ML) directions and trends of greater muscle activity were found in those older adults who demonstrated lower scores on clinical measures of balance. In addition, short-term postural sway was found to be significantly correlated with muscle activity in each of these groups. This work suggests that high levels of muscle activity are a characteristic of age-related declines in postural stability and that such activity is correlated with short-term postural sway. It is unclear whether increases in muscle activity preclude greater postural instability or if increased muscle activity is a compensatory response to increases in postural sway.
This review considers the biomechanical factors that are relevant to success in the game of soccer. Three broad areas are covered: (1) the technical performance of soccer skills; (2) the equipment used in playing the game; and (3) the causative mechanisms of specific soccer injuries. Kicking is the most widely studied soccer skill. Although there are many types of kick, the variant most widely reported in the literature is the maximum velocity instep kick of a stationary ball. In contrast, several other skills, such as throwing-in and goalkeeping, have received little attention; some, for example passing and trapping the ball, tackling, falling behaviour, jumping, running, sprinting, starting, stopping and changing direction, have not been the subject of any detailed biomechanical investigation. The items of equipment reviewed are boots, the ball, artificial and natural turf surfaces and shin guards. Little of the research conducted by equipment manufacturers is in the public domain; this part of the review therefore concentrates on the mechanical responses of equipment, player-equipment interaction, and the effects of equipment on player performance and protection. Although the equipment has mechanical characteristics that can be reasonably well quantified, the player-equipment interaction is more difficult to establish; this makes its efficacy for performance or protection difficult to predict. Some soccer injuries may be attributable to the equipment used. The soccer boot has a poor protective capability, but careful design can have a minor influence on reducing the severity of ankle inversion injuries. Performance requirements limit the scope for reducing these injuries; alternative methods for providing ankle stability are necessary. Artificial surfaces result in injury profiles different from those on natural turf pitches. There is a tendency for fewer serious injuries, but more minor injuries, on artificial turf than on natural turf pitches. Players adapt to surface types over a period of several games. Therefore, changing from one surface to another is a major aetiological factor in surface-related injuries. Heading the ball could lead to long-term brain damage. Simulation studies suggest the importance of ball mass, ball speed and player mass in affecting the severity of impact. Careful instruction and skill development, together with the correct equipment, is necessary for young players. Most applications of biomechanical techniques to soccer have been descriptive experimental studies. Biomechanical modelling techniques have helped in the understanding of the underlying mechanisms of performance, although their use has been limited. It is concluded that there are still many features of the game of soccer that are amenable to biomechanical treatment, and many opportunities for biomechanists to make a contribution to the science of soccer.
OBJECTIVE: To investigate the effect of a 10-week training programme on persons with a lower limb amputation and to determine if this training is sufficient to enable running.
SUBJECTS: Seven transtibial, 8 transfemoral and 1 bilateral amputee (all resulting from trauma, tumour or congenital) were randomly assigned to a training (n =8) or control group (n = 8).
METHODS: Isokinetic hip flexor and extensor strength at 60 and 120º/s and oxygen consumption while walking at 1.0 m/s were tested pre- and post- a 10-week period. The training group followed a twice weekly hip strengthening programme, while the control group continued with their usual activities. Running ability was determined pre-testing, and attempted after post-testing for the training group only.
RESULTS: The training group increased hip strength and decreased oxygen consumption. Six amputees who were previously unable to run were able to after training. The control group decreased intact limb hip extensor strength.
CONCLUSION: The training programme is sufficient to improve hip strength and enable running in persons with a lower limb amputation. As hip strength was reduced in those not following the training programme, it is recommended that strength training be undertaken regularly in order to avoid losing limb strength following amputation.
Amputee sport performance has greatly improved over the past 20 years along with the development of carbon fibre prostheses. As the margins between winning and losing become smaller, athletes increasingly rely on prosthetic limb technology to give them an edge over other competitors and break existing records. Originally, the aim of improving prostheses was to try to increase performance by reducing the functional disadvantage of the prosthetic foot compared to the human foot. However, claims have been made recently that not only have the functional disadvantages been redressed, but today's sprint prostheses may provide a mechanical advantage over the human limb. This review will present what is currently known about carbon fibre prostheses and their effect on the running technique of transtibial amputees.
The aim of this study was to compare hip strength in sports-active transtibial (TT) amputees, sedentary TT amputees and sports-active non-amputees. Three 'active' (exercising recreationally at least three times per week) TT amputees, four 'inactive' or sedentary TT amputees and nine 'active' able-bodied persons (AB) underwent concentric and eccentric hip flexion and extension strength testing on both limbs on an isokinetic dynamometer at 60 and 120 degrees /s. Little strength asymmetry was noted between the limbs of the active TT amputees (8% and 14% at 60 and 120 degrees /s, respectively), their residual limb being slightly stronger. Inactive TT amputees demonstrated up to 49% strength asymmetry, their intact limb being the stronger. Active TT amputees demonstrated greater peak hip torques (Nm/kg) for all conditions and speeds compared to inactive TT amputees. Peak hip torques (Nm/kg), were greater in the active TT amputees' residual limb compared to AB. While inactive TT amputees and AB had similar flexion/extension ratios, active TT amputees exhibited a lower ratio indicating overdeveloped hip extensors with respect to their hip flexors. It is not known whether this is due to the demands of sport or exercise with a prosthetic limb, or remaining residual thigh atrophy.
This study investigated sex and age differences in standing balance. Movement of the centre of pressure (COP) was calculated from ground reaction force data collected from a force platform during bipedal stance with eyes open and eyes closed. Three groups of 60 children, with 30 girls and 30 boys in each, were assessed. Mean ages of each group were as follows: 9 years 11 months (standard deviation [SD] 3mo); 12 years 11 months (SD 2mo); and 15 years 11 months (SD 3mo) respectively. Summary sway parameters and frequency domain variables were calculated in the anteroposterior and mediolateral directions. Boys exhibited greater COP movement than girls at 9 to 10 years of age. Age-related 'improvements' in sway occurred in boys, thus some aspects of postural control are still developing after 9 to 10 years of age. As very little age-related difference was seen in girls, boys may lag behind somewhat in terms of developing postural control. Thus there is a need to study the sexes separately when investigating balance in children.
Gait initiation from toe-standing is common in patients with upper motor neurone (UMN) pathology as well as in able-bodied subjects during certain dance and athletic situations. It is unclear whether balance problems in patients who toe-walk are due to the underlying pathology, or due to initiating gait from toe-standing. The aim of this study was to compare the biomechanics of gait initiation from toe-standing to that from heel-toe standing in healthy able-bodied subjects. Data were collected for three seconds prior to, and three seconds after, a visual signal to initiate gait. Ground reaction force and centre of pressure (COP) data were collected with an AMTI force platform, and electromyographic and kinematic data were collected from each limb with a Vicon motion analysis system. When initiating gait from toe-standing, there was a smaller backward displacement of the COP compared to heel-toe standing. In addition, greater forward momentum was generated, and there was an increase in gastrocnemius, rectus femoris and biceps femoris muscle activity. There were no differences in COP displacement or momentum generated in the mediolateral direction for the two conditions. Thus, initiating gait from toe-standing allows one to generate greater amounts of forward momentum but not at the expense of generating excessive stance-side momentum. This may be an advantageous method of initiating movement for dancers and athletes in certain situations. This work also suggests that balance problems in patients with UMN pathology are likely due to the underlying pathology and are not due to initiating gait from toe-standing.
Toe-standing is observed in a number of populations who are able to stand without loss of balance and also those who have balance problems. Intuitively, individuals who stand on their toes are able to successfully regulate their whole body movement in order to keep themselves stable. Force platform data were collected for ten able-bodied subjects during three quiet standing postures, (a) heel-toe standing; (b) half-toe standing and (c) standing en demi pointe (full toe-standing). Differences in control mechanisms with each posture were compared using stabilogram diffusion analysis. During open-loop control (short-term), toe-standing is less stable than heel-toe standing (P<0.05). There is greater stochastic activity when toe-standing (P<0.05), suggesting that any short-term instability is being compensated for by an increase in muscle activity across the lower joints. During closed-loop control (long-term), there is no difference in mediolateral (ML) stochastic activity (increased activity has been linked to falls) between toe-standing and heel-toe standing. In addition, toe-standing is more stable than heel-toe standing (P< s0.05). Toe-standing, in and of itself, may not be responsible for balance problems in populations who compulsorily toe-stand.
The aim of this study was to investigate the loading demands placed on the intact limb in terms of joint moments and power for active trans-femoral and trans-tibial amputees in comparison to a group of able-bodied subjects. Four (4) trans-tibial, 4 trans-femoral amputees and 10 able-bodied subjects walked at 1.2m.s(-1) along a walkway whilst kinematic data from both the intact and prosthetic limbs, and kinetic data from the intact limb only were collected. A Panasonic VHS video camera was used to film subjects walking in the sagittal plane with simultaneous force data collected from a Kistler force platform. The amputees were found to compensate for the functional loss of one or more joints by increasing net joint moments and power output on their intact limb compared to able-bodied subjects. At the intact limb ankle, the range of motion, peak dorsiflexor moment and power generation at toe-off increased. At the intact limb knee, power generation during stance and extensor moments and power absorption at toe-off increased. At the intact limb hip, extensor moment and power absorption during stance, and hip flexor moment and power generation at toe-off increased. These findings were partly attributed to the prostheses used but mainly to adaptation mechanisms displayed by trans-femoral and trans-tibial amputees. They have implications for the mobility of amputees and the long term health of their joints. It was recommended that prosthesis design, prosthesis fitting and training in the use of the prosthesis were all factors which could be investigated with a view to minimising intact limb loading.
The aims of this study were to establish the take-off characteristics of long jump performance of disabled amputee athletes, and to establish to what extent amputee athletes conform to a model of performance defined for elite able-bodied athletes. The jumps of 8 male below-knee (trans-tibial) and 8 male above-knee (trans-femoral) amputee athletes who competed in the finals of the long jump at the 1998 World Disabled Championships were recorded in the sagittal plane on video (50 Hz). Approach speed was measured using a laser Doppler system. The best jump for each athlete was digitized, and kinematic data from the key instants of touch-down (TD), maximum knee flexion (MKF) and take-off (TO) were obtained. Amputees demonstrated a lower approach speed and jumped less far than able-bodied athletes although below-knee amputees performed better than above-knee amputees. For each amputee group there was a significant (p < 0.05) linear relationship between approach speed and distance jumped. With the exception of their slower horizontal speed and greater negative vertical speed at touch-down, below-knee amputees demonstrated characteristics of technique that were similar to elite able-bodied long jumpers. Above-knee amputees at touchdown had a more upright trunk, smaller hip and knee angles and consequently a smaller leg angle. This was attributed to the difficulty of taking off on the last stride on the prosthetic limb. Consequently, above-knee amputees were less able to gain vertical velocity during the compression (TD-MKF) phase, but were able to compensate for this by using a greater hip range of motion during the extension (MKF-TO) phase. It was concluded that below-knee amputees displayed the same basic jumping technique as elite able-bodied long jumpers, but above-knee amputees did not. These findings have implications for the training and technical preparation of amputee long jumpers.
In this study, we investigated the adjustments to posture, kinematic and temporal characteristics of performance made by lower limb amputees during the last few strides in preparation for long jump take-off. Six male unilateral trans-femoral and seven male unilateral trans-tibial amputees competing in a World Championships final were filmed in the sagittal plane using a 100-Hz digital video camera positioned so that the last three strides to take-off were visible. After digitizing using a nine-segment model, a range of kinematic variables were computed to define technique characteristics. Both the trans-femoral and trans-tibial athletes appeared to achieve their reduction in centre of mass during the flight phase between strides, and did so mainly by extending the flight time by increasing stride length, achieved by a greater flexion of the hip joint of the touch-down leg. The trans-tibial athletes appeared to adopt a technique similar to that previously reported for able-bodied athletes. They lowered their centre of mass most on their second last stride (-1.6% of body height compared with -1.4% on the last stride) and used a flexed knee at take-off on the last stride, but they were less able to control their downward velocity at touch-down (-0.4 m x s(-1)). Both this and their restricted approach speed (8.9 m x s(-1) at touch-down), rather than technique limitations, influenced their jump performance. The trans-femoral athletes lowered their centre of mass most on the last stride (-2.3% of body height compared with -1.6% on the second last stride) and, as they were unable to flex their prosthetic knee sufficiently, achieved this by abducting their prosthetic leg during the support phase, which led to a large downward velocity at touch-down (-0.6 m x s(-1)). This, combined with their slower approach velocity (7.1 m x s(-1) at touch-down), restricted their performance.
An analysis of the take-off technique in transtibial amputee high jump was performed on two athletes (both using intact limb take-off) competing in the high jump finals of the 2004 Paralympic Games. Two digital video cameras were used to film the event with the data later digitized and reconstructed using standard 3D direct linear transformation (DLT) procedures. Some similarities with non-amputee high jump technique were noted in that centre of mass height was low at touch-down (TD), there was a similar magnitude of negative vertical velocity at TD, and most of the vertical velocity generated occurred in the first half of the take-off phase. However, both transtibial amputee athletes exhibited a slower horizontal approach velocity, a lower positive vertical take-off velocity, a more upright position at touch-down and a greater range of motion of the hip throughout the take-off phase compared to what is known about non-amputee high jump technique. These differences may be associated with constraints of taking off from the prosthetic limb on the previous step, resulting in having to adopt a different posture at touch-down compared to non-amputees. Understanding transtibial amputee high jump technique and the differences compared to what is known about non-amputee technique has implications for coaching and improving performance in prosthetic sport.
PURPOSE: The purpose of this study was to investigate whether female lower-limb amputees conform to the established long-jump model and to compare the kinematics of the approach and take-off phases for elite female transfemoral and transtibial amputee long jumpers. METHODS: Eight female transfemoral and nine female transtibial amputee athletes were videotaped (sagittal plane movements at 50 Hz) from third-to-last step to take-off during the 2004 Paralympic Games long-jump finals. After digitizing and reconstruction of 2D coordinates, key variables were calculated at each stride and during contact with the take-off board. Additionally, approach speed during the run-up of each jump was recorded (100 Hz) using a laser Doppler device (LDM 300 C Sport, Jenoptik Laser, Jena, Germany). RESULTS: The transfemoral amputees had a consistently higher center of mass height on the last three steps before take-off than the transtibial amputees. However, at touch-down onto the take-off board, they lowered their center of mass excessively so that from touch-down to take-off, they were actually lower than the transtibial amputees. This resulted in a greater negative vertical velocity at touch-down and may have inversely affected their jump performance. CONCLUSION: Female transtibial athletes conformed to the long-jump model, although adaptations to this technique were displayed. Female transfemoral athletes, however, exhibited no relationship between take-off speed and distance jumped, which may be attributable to their excessive lowering of their center-of-mass height at touch-down onto the take-off board. It is recommended that coaches and athletes proceed with caution when trying to replicate techniques used by able-bodied athletes because adaptations to the constraints of a prosthesis should be considered.
The purpose of this study was to evaluate the extent to which residual shank length affects long jump performance of elite athletes with a unilateral transtibial amputation. Sixteen elite, male, long jumpers with a transtibial amputation were videoed while competing in major championships (World Championships 1998, 2002 and Paralympic Games, 2004). The approach, take-off, and landing of each athlete's best jump was digitized to determine residual and intact shank lengths, jump distance, and horizontal and vertical velocity of center of mass at touchdown. Residual shank length ranged from 15 cm to 38 cm. There were weak, nonsignificant relationships between residual shank length and (a) distance jumped (r = 0.30), (b) horizontal velocity (r = 0.31), and vertical velocity (r = 0.05). Based on these results, residual shank length is not an important determinant of long jump performance, and it is therefore appropriate that all long jumpers with transtibial amputation compete in the same class. The relationship between residual shank length and key performance variables was stronger among athletes that jumped off their prosthetic leg (N = 5), and although this result must be interpreted cautiously, it indicates the need for further research.
The effect of increased walking speed on temporal and loading asymmetry was investigated in highly active trans-femoral and trans-tibial amputees. With increasing walking speed, temporal gait variables reduced in duration, particularly on the prosthetic limb, while vertical ground reaction force (vGRF) increased in magnitude, particularly on the intact limb. Thus, temporal asymmetry reduced and loading asymmetry increased with walking speed. The greater force on the intact limb may reflect the method by which the amputees achieve greater temporal symmetry in order to walk fast, and could possibly account for greater instances of joint degeneration in the intact limb reported in the literature.
Appropriate muscular response following an external perturbation is essential in preventing falls. Transtibial prosthesis users lack a foot-ankle complex and associated sensorimotor structures on the side with the prosthesis. The effect of this lack on rapid responses of the lower limb to external surface perturbations is unknown. The aim of the present study was to compare electromyogram (EMG) response latencies of otherwise healthy, unilateral, transtibial prosthesis users (n = 23, mean +/- standard deviation [SD] age = 48 +/- 14 yr) and a matched control group (n = 23, mean +/- SD age = 48 +/- 13 yr) following sudden support-surface rotations in the pitch plane (toes-up and toes-down). Perturbations were elicited in various weight-bearing and limb-perturbed conditions. The results indicated that transtibial prosthesis users have delayed responses of multiple muscles of the lower limb following perturbation, both in the intact and residual limbs. Weight-bearing had no influence on the response latency in the residual limb, but did on the intact limb. Which limb received the perturbation was found to influence the muscular response, with the intact limb showing a significantly delayed response when the perturbation was received only on the side with a prosthesis. These delayed responses may represent an increased risk of falling for individuals who use transtibial prostheses.