Sammanfattning Syfte och frågeställningar. Syftet med denna studie var att på äldre personer studera olika fysiologiska parametrar före och efter en period på åtta veckor med styrketräning som utförs tre gånger i veckan. Frågeställningarna var: Hur påverkas statisk och dynamisk maximal styrka i främre lårmuskulaturen av styrketräning? Är det någon skillnad i resultat mellan koncentrisk och excentrisk styrka i lårmuskulaturen före och efter styrketräningsperioden? Är det någon skillnad i förändring mellan benstyrka uppmätt med isokinetisk teknik jämfört med uthållighetsstyrka och ett kort funktionellt benstyrketest? Hur påverkas maximal syreupptagningsförmåga registrerad via submaximalt cykeltest respektive vid pyramidtestet av träningsperioden? Metod. I studien deltog 20 generellt ej påtagligt aktiva män och kvinnor i åldrarna 66-79 år. Av dessa var 11 individer slumpvis indelade i en styrketräningsgrupp och övriga nio utgjorde en inaktiv kontrollgrupp. Ett flertal olika fysiologiska tester, som bl.a. prövade testpersonernas styrka samt kondition, utfördes innan och efter träningsperioden. De deltagare som utgjorde träningsgruppen tränades i relativt tung styrketräning i åtta veckor. Resultat. Undersökningen resulterade i en signifikant ökad koncentrisk-, excentrisk- samt statisk momentan benstyrka för träningsgruppen efter de åtta veckorna med relativt tung styrketräning. Vidare kunde även utläsas för dem en signifikant förbättring av uthållighetsstyrka i benen (hastighet vid 50 uppresningar från stol, med 16,9 %) samt vid ett kort funktionellt test (5 uppresningar från stol, med 12,8 %). De träningsgenererade signifikanta ökningarna för träningsgruppen tyder inte på några stora procentuella skillnader mellan statisk (10,4 %) och dynamisk excentrisk (7,8 %) eller koncentrisk maximal styrka (9,5 %). Vid testerna cykelergometertest (kondition), effekt i 5-minuterspyramidtest (ett modifierat steptest) samt distans vid 6-minuters gångtest framkom inga signifikanta förbättringar för träningsgruppen. Ingen i kontrollgruppen visade en signifikant förbättring i någon av de nämnda testerna. Slutsats. Studien visar att interventioner, med åtta veckors intensiv styrketräning, tre gånger per vecka för äldre kvinnor och män, påtagligt kan förbättra resultaten vid styrkemätningar såväl momentant som uthållighetsmässigt och vid ett kort funktionellt test, medan tester av maximal syreupptagningsförmåga (VO2max) inte förbättras. Emellertid framkom i cykelergometertestet en tendens till förbättring för träningsgruppen.

Knee function was evaluated by knee score, activity level, clinical findings and performance tests, muscle size by computerized tomography (CT), morphology by light (LM) and electron microscopy (EM), muscle function by electromyography (EMG) and isokinetic performance in 29 patients with chronic anterior cruciate ligament (ACL) tear. Preoperatively CT disclosed a significant mean atrophy of the quadriceps and nonsignificant changes of the other muscle areas of the injured leg. Morphology of m vastus lateralis of the injured leg was normal in more than half of the biopsies preoperatively, the rest showed signs of nonoptimal activation. Significant decreases in all isokinetic parameters were noticed together with significantly decreased EMG of the quadriceps muscle of the injured leg. Âfter surgical reconstruction the knees were immobilized in a cast for 6 weeks at either 30° or 70° of knee flexion. After cast removal CT showed significant decreases of all areas which also remained after training. The 30° group showed larger fibres (intracellular oedema) and more frequent morphological abnormalities than the 70° group. Fourteen weeks postoperatively the patients were allocated to either a combination of isometric and progressive resistance training or isokinetic training for 6 weeks. CT showed slightly larger areas at 20 weeks postoperatively than at 6 weeks. Morphological abnormalities were still prominent at 20 weeks postoperatively. Maximum isokinetic knee extensor mechanical output and endurance were markedly decreased at 14 weeks postoperatively but both improved progressively during the one year rehabilitation, mostly during the intensive 6 week training period but irrespective of training programme used. Fatiguability/endurance level improved over the preoperative level. Muscular work/integrated EMG was stable while EMG/t increased indicating neuromuscular relearning. The clinical result at 28 months foliowup was excellent or good in 93% of the patients and clinical stability improved in 66%. Independent upon primary knee immobilization angle or training programmes no differences could be demonstrated with respect to stability, range of motion, function or isokinetic mechanical output. Isokinetic performance was still significantly lower in the injured compared to the noninjured leg and not significantly different from the preoperative values. Morphology, only 6 cases, showed abnormalities similar to preoperative findings. In conclusion, the reason for the decreased maximum and total knee extensor performance in these patients with ACL tears is suggested to be nonoptimal activation of normal functioning muscle fibres depending on changes in knee joint receptor afferent inflow. No differences concerning the markedly improved postoperative clinical result could be seen between the different treatment modalities used. A nonoptimal muscular activation might explain the still decreased isokinetic performance present at followup. / <p>S. 1-40: sammanfattning, s. 43-137: 5 uppsatser</p> / digitalisering@umu.se

The purpose of this study was to determine the vastus medialis oblique muscular electromyographical (EMG) activity during two therapeutic exercises: the modified straight leg raise and the traditional straight leg raise. Two subject groups of 10 subjects each, one with anterior knee pain (PHY) and the other group with no history of patellofemoral pathology (NORM), performed the traditional straight leg raise (SLR) and a modified straight leg raise with external hip rotation (MOD). Each subject performed an isometric maximum voluntary contraction and three trials of each of the two therapeutic exercises. The EMG variables analyzed were the percent of the maximum voluntary contraction for each muscle, vastus medialis oblique, vastus lateralis, and rectus femoris: the percent of the maximum voluntary contraction of the ratio between the vastus medialis oblique and the vastus lateralis; the percent of the maximum voluntary contraction for the integrated EMG for each muscle; and the percent of the maximum voluntary contraction for the root mean square for each muscle. The statistical analysis was conducted with two-way analysis of variance procedures. The statistical analysis revealed no significant differences; however, the data appeared to illustrate a trend toward more electromyographical activity in the vastus medialis oblique in the PHY subject group during the MOD therapeutic exercise. This suggests that the MOD therapeutic exercise may be able to isolate the vastus medialis oblique muscle in persons with anterior knee pain and allow them to regain strength and normal function earlier than with the use of the SLR therapeutic exercise. / School of Physical Education

The purpose of this study was to determine the jump landing impact absorption kinematic and kinetic characteristics of the four subject groups: a) male high school athletes, b) female high school seasonal athletes, c) female high school year-round athletes, and d) female college athletes who train year-round. Subjects dropped onto a force platform from a height of 40 centimeters. Variables analyzed were flexibility, strength, Fz, Fy, and Fx force, free moment, range of motion, contact and maximum angles, time to maximum angle, contact and maximum angular velocities, and time to maximum angular velocity. Significant differences among subject groups were determined through use of a factorial analysis of variance and Scheffe' post hoc test.A difference was noted in the landing patterns of males and females. Male subjects exhibited a significantly longer time to first vertical peak force. This longer time may allow for greater initial force attenuation; however, the male athletes had a significantfy greater second peak force. Males also differed significantly from females in anteroposterior and mediolateral force.The differences in method of force attenuation may be due to significantly greater ankle eversion shown by the males and greater knee flexion used by the females. Additionally, the males had significantly greater leg strength, which may have allowed them to increase the time to first peak.The year round female high school athletes were found to use the best biomechanical landing method. They had a greater range of motion in the knee and ankle, and subsequently produced the lowest amount of vertical and anterio-posterior force. / School of Physical Education

The purposes of this study is to determine: (a) the relationship between the dependant variables, (b) the relationship between the Borg pain scale and the performance tests, (c) the difference in performance between involved and uninvolved extremities, and (d) the effects of the three different therapeutic exercise treatments on selected performance tests and pain free isometric strength testing. Fifty subjects with physician diagnosed anterior knee pain (AKP), completed initial performance testing and 14 subjects completed initial testing, therapy and six weeks later final performance testing. The 14 subjects were randomly assigned to one of three therapeutic exercise treatment groups. The performance tests included; pain free isometric strength tests (90, 60, 45, and 15 degrees knee flexion), stair test, timed hop, triple hop, crossover hop, Figure 8 and Borg pain scale rating for each performance test. The results indicated a significant correlation between performance tests and pain free isometric strength tests. There was no relationship indicated between the performance tests, Borg pain scale ratings. The contrast between the injured and uninjured extremities performance test values of the fifty subjects that completed the initial testing indicated no significant (p< 0.05) difference. The results of this study indicated that there was no significant difference between the therapeutic exercise treatment groups. In conclusion, the three anterior knee pain treatments had no effect on strength and performance. / School of Physical Education

Syfte Syftet med föreliggande studie var att undersöka genomförbarheten av en hög-intensiv träningsintervention efter knäplastikoperation samt hur knäplastikopererade personers självvalda gånghastighet, maximal vadmuskelstyrka, vadmuskeluthållighet och självupplevda symptom, smärta, ADL funktion och hälsorelaterad livskvalité påverkas av tidigt insatt hög-intensiv styrketräning av vadmuskulaturen. Metod Femton forskningspersoner randomiserades till en träningsgrupp (n=7), som utförde hemträningsprogram i form av hög-intensiv vadmuskelträning samt till en kontrollgrupp (n=8) som utförde samma rehabiliteringsprogram som träningsgruppen utan hög-intensiv vadmuskelträning. En testprocedur genomfördes 3 respektive 12 veckor efter knäplastikoperationen. Självvald gånghastighet mättes genom ett 30 meters gångtest, vadmuskeluthållighet mättes med ett standardiserat tåhävningstest på ett ben, maximal isometrisk vadmuskelstyrka mättes med hjälp av en isometrisk dynamometer och självskattad symptom, smärta, ADL funktion och livskvalité utvärderades genom Knee injury Osteoarthritis Outcome Score (KOOS). Resultat Denna studie påvisar viss problematik med följsamheten i träningsregim för båda grupperna. Båda gruppernas sammanslagna resultat uppvisade signikant förbättrad självvald gånghastighet, maximal vadmuskelstyrka och uthållighet över tid. Trots detta ökade träningsgruppen den självvalda gånghastigheten signifikant mer än kontrollgruppen över tid. Träningsgruppen hade även mindre besvär på grund av smärta 12 veckor efter operationen. Båda gruppernas sammanslagna resultat förbättrades över tid gällande deras egen skattning av symptom, smärta, ADL funktion och livskvalité. Däremot förbättrade träningsgruppen alla variabler signifikant medan det för kontrollgruppen endast var livskvalitén som förbättrades signifikant över tid. Konklusion Tidigt insatt hög-intensiv vadmuskelträning efter knäplastikoperation är genomförbart och kan ha en viss positiv effekt på personens egen upplevelse av symtom, smärta, funktion och hälsorelaterad livskvalité. Självvald gånghastighet förefaller öka mer vid tidigt insatt hög-intensiv vadmuskelträning efter nio veckors träning jämfört med samma rehabiliteringsprogram utan hög-intensiv vadmuskelträning. / Aim The aim of this study was to determine the feasibility of a high-intensive exercise intervention following a knee arthroplasty, and also to evaluate possible effects on self-selected walking speed, calf muscle strength and self-rated symptoms, pain, ADL function and quality of life after high-intensive calf muscle training in an early post-operative phase. Method Fifteen participants were randomized into an exercise group (n=7), who performed a home-exercise program, consisting of high-intensive calf muscle exercise, and into a control group (n=8) who performed the same rehabilitation program but without the high-intensive calf muscle training. A test procedure was conducted after 3 and 12 weeks following the knee arthroplasty. Self-selected walking speed was measured by a 30 meter walking test, calf muscle endurance training was measured with a standardized one-leg heel-rise test, maximal isometric calf muscle strength was measured with an isometric dynamometer, and self-rated symptom, pain, ADL function and quality of life were evaluated with Knee injury Osteoarthritis Outcome Score (KOOS). Results There were problems with adherence to exercise regimes in both groups. The results of both groups demonstrated improved self-selected walking speed, calf muscle endurance and maximal isometric calf muscle strength over time. However, the exercise group increased self-selected walking speed more than the control group. The exercise group reported fewer disorders due to pain 12 weeks after surgery. The results of both groups showed improved self-rated symptoms, pain, ADL function and quality of life over time, however, the exercise group improved all these variables significantly, while the control group significantly improved the quality of life aspect. Conclusions Early initiated high-intensive calf-muscle training following a knee artroplasthy is feasible and may have positive effects on self-rated symptoms, pain, ADL function and quality of life. Also, self-selected walking speed increased more with early initiated high-intensive calf muscle training after nine weeks when compared to the same rehabilitation program without high-intensive calf muscle training.

The primary purpose of this study was to determine the ratio of activation between the VMO and VL while performing three selected knee exercises (drop squat, modified lateral squat, Muncie Method). Additionally, the data was analyzed to determine if a correlation existed between the muscle's activation rate per set and whether or not the rates are affected by Q-angle or gender. Twenty Ball State University subjects (10 male, 10 female) who were asymptomatic to Patellofemoral Syndrome (PFS), provided electroymyographic (EMG) data while performing the three selected exercises. A one-way ANOVA found no statistical significance (p=0.500) on any of the tested variables except the Drop Squat VL Root Mean Square (RMS). Significant correlations were found between: VL RMS to set number during drop squat, and VMO and VL RMS to set number during Muncie Method performance. Based on the results of this study, each of these exercises could be used to selectively strengthen the VMO in treatment of PFS. / School of Physical Education

The purpose of this investigation was to examine the effects of Multiple Sclerosis (MS) on the structural and functional characteristics of skeletal muscle. More specifically, we analyzed the myosin heavy chain (MHC) and fiber type distribution of the vastus lateralis, measured single fiber cross sectional area (CSA), and determined the isokinetic and isotonic strength of the knee extensor muscles. Six sedentary subjects with MS (age: 44 ± 2 yrs) and six sedentary gender-matched controls (age: 46 ± 4) were evaluated. EachMS subject was rated on the Kurtzke's Expanded Disability Status Scale (EDSS) and performed an 8-meter walk test to determine gait speed. Furthermore, the spasticity of the knee extensors was evaluated in each MS subject and weekly energy expenditure was estimated using the Yale Physical Activity Survey. Concentric and eccentric isokinetic strength of the right knee extensors (left in one MS subject) was determined at 60 and 180°/sec and a bilateral isotonic one-repetition maximum (1-RM) was evaluated in eachsubject. Muscle biopsies were taken from the right vastus lateralis (left in one MS subject) and individual fibers were dissected from these samples. Fibers were submitted to SDSPAGE with silver staining to determine MHC expression. Densitometry was performed on MHC hybrid fibers to determine the degree of co-expression. An additional section ofthe biopsy was stained for mATPase activity and further analyzed for single fiber CSA and fiber type. The mean EDSS score for the MS subjects was 5.4 ± 0.6 (range 3.5-6.5) and MS patients were slower than controls (p < 0.05) on the walk-test. AshworthSpasticity Scores ranged from 0 - 2. No differences were noted in weekly energy expenditure. The controls were 45 and 56% stronger than the MS group at isokinetic concentric velocities of 60 and 180°/sec (p < 0.05), respectively. The isotonic 1-RM andthe eccentric isokinetic contractions were not different between the two groups. There were no differences noted in any of the MHC isoforms or percentage of hybrid fibers. Furthermore, mATPase fiber type distribution and single fiber CSA were not different between the groups. There was a greater proportion of MHC IIx dominant MHC IIa/IIx fibers in the MS groups (p < 0.05). Multiple Sclerosis appears to result in large strengthdeficits, when compared to healthy individuals. Based on our findings, these strength differences cannot be explained by alterations in MHC/fiber type expression or decreases in fiber CSA. / School of Physical Education

Neuromuscular control is believed to play an essential role during dynamic knee joint stabilisation. Evaluation of voluntary muscle action can be delineated as support strategies against external loading moments (Lloyd & Buchanan, 2001). The aim of this study was to determine if males and females exhibit differences in knee muscle action and cocontraction during voluntary isometric closed kinetic chain force generation in various directions in the horizontal plane representative of applied loads transverse to the long axis of the shank. Twenty-six healthy young adults (13 male, 13 female) stood with their dominant leg in a boot fixed to a force platform. A force target matching protocol required subjects to position a cursor (projected on a video screen) over a target and maintain the position for one second. To control the cursor, loads were applied against the force platform with their dominant leg to produce various combinations of anterior-posterior, medial-lateral loads while maintaining constant inferior-superior loads. A successful target match required a normalised force magnitude of equal effort for each subject and target location which triggered the recording of electromyography (EMG) for eight muscles crossing the knee joint. EMG was normalised to percent maximum voluntary isometric contraction. A mean magnitude of muscle activation, mean direction of muscle activation and a muscle specificity index was determined using EMG vectors. In addition, cocontraction indices were also computed for antagonist muscle pairs. Based on similar previous research, it was hypothesised that females would have greater quadriceps and hamstrings coactivation, greater muscle activation magnitudes, lower specificity for the quadriceps than males and no difference in hamstring characteristics. In our study, females significantly cocontracted their vastus lateralis and lateral gastrocnemius muscles to a greater degree than males (p=0.001). No significant differences were observed across sexes for the cocontraction of quadriceps and hamstrings or the lateral quadriceps and gastrocnemius muscles. Females displayed significantly lower specificity than males in their semitendinosus (p=0.025) and tensor fascia lata (p=0.012) activity patterns, greater magnitude of muscle activation in their lateral gastrocnemius (p=0.002) and tensor fascia lata (p<0.003) and no statistical difference in the other muscles. Furthermore, the activation patterns in our study grossly differed from previous open kinetic chain force target matching. These findings indicate that healthy young males and females have differences in their knee muscle control strategies and that knee muscle recruitment patterns differ during weight bearing and non-weight bearing tasks.

The Ottawalk-Speed (OWS) orthosis prevents knee collapse in stumble situations. The purpose of this study was to develop a virtual stumble perturbation to measure OWS response to a knee collapse when walking. A new split speed perturbation was developed for the CAREN virtual reality system. This perturbation induced a stumble with increased knee flexion for five able-bodied participants, with either a hopping or stopping recovery strategy. Three knee-ankle-foot orthosis users were subjected to five stumble trials while wearing the OWS. OWS participants used a straight-legged recovery strategy, and extended the knee through recovery weight acceptance. Therefore, the split speed perturbation was not appropriate to measure OWS response to a stumble since knee collapse did not occur. The OWS allowed free knee motion during gait. Further study is required to measure OWS response during a stumble with a knee collapse event.