Isokinetic Plantar Flexion Strength Research Articles

Absorbable versus nonabsorbable sutures for the Krackow suture repair of acute Achilles tendon rupture: a prospective randomized controlled trial.

Although absorbable sutures for the repair of acute Achilles tendon rupture (ATR) have been attracting attention, the rationale for their use remains insufficient. This study prospectively compared the outcomes of absorbable and nonabsorbable sutures for the repair of acute ATR. A total of 40 patients were randomly assigned to either braided absorbable polyglactin suture or braided nonabsorbable polyethylene terephthalate suture groups. ATR was then repaired using the Krackow suture method. At three and six months after surgery, the isokinetic muscle strength of ankle plantar flexion was measured using a computer-based Cybex dynamometer. At six and 12 months after surgery, patient-reported outcomes were measured using the Achilles tendon Total Rupture Score (ATRS), visual analogue scale for pain (VAS pain), and EuroQoL five-dimension health questionnaire (EQ-5D). Overall, 37 patients completed 12 months of follow-up. No difference was observed between the two groups in terms of isokinetic plantar flexion strength, ATRS, VAS pain, or EQ-5D. No re-rupture was observed in either group. The use of absorbable sutures for the repair of acute ATR was not inferior to that of nonabsorbable sutures. This finding suggests that absorbable sutures can be considered for the repair of acute ATRs. Cite this article: Bone Joint J2022;104-B(8):938-945.

Stretch-Shortening Cycle Performance and Muscle-Tendon Properties in Dancers and Runners.

The purpose of this investigation was to elucidate whether ankle joint stretch-shortening cycle performance, isometric and isokinetic plantarflexion strength, and maximal Achilles tendon force and elongation differ between dancers, endurance runners, and untrained controls. To differentiate between dancers, endurance runners, and controls, the authors measured maximal Achilles tendon force and elongation during isometric ramp contractions with ultrasonic imaging, maximal isometric and isokinetic plantarflexion strength with dynamometry, and stretch-shortening cycle function during countermovement hopping and 30-cm drop hopping with a custom-designed sled. The Achilles tendon of dancers elongated significantly (P ≤ .05) more than runners and controls. Dancers were significantly stronger than controls during isometric contractions at different ankle angles. Concentric and eccentric strength during isokinetic contractions at 60°·s-1 and 120°·s-1 was significantly higher in dancers and runners than controls. Dancers hopped significantly higher than runners and controls during hopping tasks. Dancers also possessed significantly greater countermovement hop relative peak power, drop hop relative impulse, and drop hop relative peak power than controls. Finally, dancers reached significantly greater velocities during countermovement hops than runners and controls. Our findings suggest dancing and running require or likely enhance plantarflexion strength. Furthermore, dancing appears to require and enhance ankle joint stretch-shortening cycle performance and tendon elongation.

Total Ankle Arthroplasty: Is Ankle Plantarflexion Strength Important?

Category:Ankle ArthritisIntroduction/Purpose:Ankle push off power, which requires gastroc-soleus muscle strength, is a critical aspect of healthy gait and increases as gait speed increases. It is therefore surprising that one-to-two-year outcomes following total ankle arthroplasty (TAA) include improved gait speed but deficient ankle power. One possible explanation for low ankle power following TAA is ankle plantarflexion weakness. Information on plantarflexion strength is extremely limited in people before or after TAA. Evaluating plantarflexion strength may inform postoperative expectations and guide rehabilitation programs. The purpose of this study was to evaluate the change in ankle plantarflexion strength, ankle power during gait, and gait speed before and after TAA in people with end-stage ankle arthritis, and in comparison to a healthy matched control group.Methods:Twenty-five participants were included in this prospective case-control study. TAA group participants (n = 13) [mean (SD): Age 60.9 (15.3) years; BMI 30.53 (5.5) Kg/m2; 85% male] with end-stage ankle arthritis who received a TAA were evaluated preoperatively and six months postoperatively. Performance of adjunct soft tissue procedures were patient specific (5/13 participants received tendo-achilles lengthening). All patients received formal physical therapy. Healthy control participants (n=12) were matched to the TAA group on age, gender and BMI. Ankle peak isokinetic plantarflexion strength (torque at 60 and 120 degrees/second; Nm/kg) was measured with an instrumented dynamometer. Peak ankle power (joint torque x segmental velocity; W/kg) was calculated via three-dimensional multi-segment foot motion analysis while participants walked barefoot over a force plate at controlled speeds. Gait speed (m/s) was measured with the Six-Minute Walk Test. Appropriate nonparametric comparisons were made to evaluate differences across time, between limbs, and between groups.Results:Compared to preoperative values, involved limb ankle strength was preserved at 60 and 120 degrees/second following TAA (both p > 0.59). Postoperative involved limb ankle strength at both speeds were 37-56% lower than the non-involved limb and control group (all p < 0.05) (Figure 1). Similarly, involved limb ankle power was preserved following TAA (p = 0.43), but remained at least 38% lower than the non-involved limb or control group (both p < .01). A subset analysis revealed that TAA participants with tendo-achilles lengthening had 25-33% less involved limb postoperative ankle power and strength than TAA participants without tendo-achilles lengthening. Interestingly, gait speed increased following TAA (p = 0.01) and was similar to control group speeds [TAA 1.5 vs. Control 1.6 m/s; p = 0.59].Conclusion:Robust improvements in gait speed were observed following TAA. These values approached normative gait speed in spite of diminished ankle strength and power. Ankle plantarflexion weakness reduces the capacity to generate ankle power during gait, regardless of possible contributing factors (i.e. preexisting atrophy/weakness, tendo-achilles lengthening). Accordingly, improvements in gait speed were likely linked to proximal joint compensations (i.e. hip, knee). The long term consequences of plantarflexion weakness may negatively affect implant loading. Study findings provide new information and point to the importance of targeting strength during postoperative TAA rehabilitation, potentially adjusting strategies for patients receiving soft tissue lengthening procedures.

Does Ankle Muscle Performance Mirror Improved Pain Following Total Ankle Arthroplasty?

Category: Ankle Arthritis Introduction/Purpose: Total ankle arthroplasty (TAA) outcomes include pain reduction and improved gait speed. Ankle push off power, which requires gastroc-soleus muscle strength, is a critical aspect of healthy gait and increases as gait speed increases. It appears that improvements in pain translate to improved ankle muscle performance. However, ankle power after TAA is surprisingly low. It is possible years of arthritis and latent muscle memory result in reduced gastroc-soleus muscle strength and a gait pattern reliant on proximal joints for power. Evaluating these hypotheses will drive postoperative care. The purpose of this ongoing prospective study is to be the first to evaluate the interplay of pain, gait speed, and ankle muscle performance (strength and power) in people following TAA for end-stage ankle arthritis. Methods: Twelve people [Mean (SD): Age 61 (14.3) years; BMI 30.0 (5.4) Kg/m2; 83% male] with end-stage ankle arthritis who were candidates for TAA participated (12 preoperative and 9 six-month postoperative visits). Performance of adjunct soft tissue procedures and postoperative care were patient specific. A twenty point numeric pain rating scale was used to measure worst pain in the past week. Three dimensional multi-segment foot motion analysis was performed while participants walked barefoot on level ground over a force plate. Ankle peak push-off power (joint torque x segmental velocity) was calculated. Ankle peak isokinetic plantarflexion strength (torque at 60 degrees / second) and ankle sagittal plane passive range of motion were measured with a dynamometer. Participants also completed the six minute walk test. Wilcoxon Signed Rank tests were used to evaluate preoperative to postoperative changes and between limb differences postoperatively. Results: Pain decreased (postoperative mean = 2.8; p = 0.01) and gait speed increased following TAA (p = 0.02). Ankle plantarflexion strength and ankle power during walking were preserved following TAA (both p &gt; 0.8) (Figure 1). Postoperative group mean dorsiflexion was 25.1 degrees and plantarflexion was 18.9 degrees, suggesting sufficient ankle motion was present for plantarflexor muscle performance. However, between limb differences were significant for both strength and power (both p &lt; 0.05) postoperatively. The involved ankle produced 36% less strength and generated 45% less power during walking in comparison to the uninvolved limb. This asymmetry demonstrates that involved limb ankle muscle performance was not normalized at six-month follow up, despite improvements in pain. Conclusion: Study findings provide preliminary evidence that improved pain and gait speed are disconnected from ankle muscle performance following TAA. Postoperative improvements in gait speed were likely driven by more proximal joints (i.e. hip). Without additional targeted postoperative plantarflexion strengthening and gait training to improve ankle muscle involvement, gains in ankle power, a symmetrical gait pattern, and patient tolerance to higher level activity (i.e. stairs) are unlikely to occur long-term. The underpinning mechanisms limiting the necessary strength to drive power generation (i.e. length-tension relationship, atrophy), and the possible cumulative effect of how abnormal gait may influence implant survivorship deserve further attention.

Tendon Length, Calf Muscle Atrophy, and Strength Deficit After Acute Achilles Tendon Rupture: Long-Term Follow-up of Patients in a Previous Study.

In this prospective study, we used magnetic resonance imaging (MRI) to assess long-term Achilles tendon length, calf muscle volume, and muscle fatty degeneration after surgery for acute Achilles tendon rupture. From 1998 to 2001, 60 patients at our center underwent surgery for acute Achilles tendon rupture followed by early functional postoperative rehabilitation. Fifty-five patients were reexamined after a minimum duration of follow-up of 13 years (mean, 14 years), and 52 of them were included in the present study. Outcome measures included Achilles tendon length, calf muscle volume, and fatty degeneration measured with MRI of both the affected and the uninjured leg. The isokinetic plantar flexion strength of both calves was measured and was correlated with the structural findings. The Achilles tendon was, on average, 12 mm (95% confidence interval [CI] = 8.6 to 15.6 mm; p < 0.001) longer (6% longer) in the affected leg than in the uninjured leg. The mean volumes of the soleus and medial and lateral gastrocnemius muscles were 63 cm (13%; p < 0.001), 30 cm (13%; p < 0.001), and 16 cm (11%; p < 0.001) lower in the affected leg than in the uninjured leg, whereas the mean volume of the flexor hallucis longus (FHL) was 5 cm (5%; p = 0.002) greater in the affected leg, indicating FHL compensatory hypertrophy. The median plantar flexion strength for the whole range of motion ranged from 12% to 18% less than that on the uninjured side. Finally, the side-to-side difference in Achilles tendon length correlated substantially with the strength deficit (ρ = 0.51, p < 0.001) and with medial gastrocnemius (ρ = 0.46, p = 0.001) and soleus (ρ = 0.42, p = 0.002) muscle atrophy. Increased Achilles tendon length is associated with smaller calf muscle volumes and persistent plantar flexion strength deficits after surgical repair of Achilles tendon rupture. Strength deficits and muscle volume deficits are partly compensated for by FHL hypertrophy, but 11% to 13% deficits in soleus and gastrocnemius muscle volumes and 12% to 18% deficits in plantar flexion strength persist even after long-term follow-up. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Soleus Atrophy Is Common After the Nonsurgical Treatment of Acute Achilles Tendon Ruptures: A Randomized Clinical Trial Comparing Surgical and Nonsurgical Functional Treatments

Background: It remains controversial whether nonsurgical or surgical treatment provides better calf muscle strength recovery after an acute Achilles tendon rupture (ATR). Recent evidence has suggested that surgery might surpass nonsurgical treatment in restoring strength after an ATR. Purpose: To assess whether magnetic resonance imaging (MRI) findings could explain calf muscle strength deficits and the difference between nonsurgical and surgical treatments in restoring calf muscle strength. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: From 2009 to 2013, 60 patients with acute ATRs were randomized to surgery or nonsurgical treatment with an identical rehabilitation protocol. The primary outcome measure was the volume of calf muscles assessed using MRI at 3 and 18 months. The secondary outcome measures included fatty degeneration of the calf muscles and length of the affected Achilles tendon. Additionally, isokinetic plantarflexion strength was measured in both legs. Results: At 3 months, the study groups showed no differences in muscle volumes or fatty degeneration. However, at 18 months, the mean differences between affected and healthy soleus muscle volumes were 83.2 cm3 (17.7%) after surgery and 115.5 cm3 (24.8%) after nonsurgical treatment (difference between means, 33.1 cm3; 95% CI, 1.3-65.0; P = .042). The study groups were not substantially different in the volumes or fatty degeneration of other muscles. From 3 to 18 months, compensatory hypertrophy was detected in the flexor hallucis longus (FHL) and deep flexors in both groups. In the nonsurgical treatment group, the mean difference between affected and healthy FHL muscle volumes was −9.3 cm3 (12%) and in the surgical treatment group was −8.4 cm3 (10%) (P ≤ .001). At 18 months, Achilles tendons were, on average, 19 mm longer in patients treated nonsurgically compared with patients treated surgically (P < .001). At 18 months, surgically treated patients demonstrated 10% to 18% greater strength results (P = .037). Calf muscle isokinetic strength deficits for the entire range of ankle motion correlated with soleus atrophy (ρ = 0.449-0.611; P < .001). Conclusion: Treating ATRs nonsurgically with a functional rehabilitation protocol resulted in greater soleus muscle atrophy compared with surgical treatment. The mean Achilles tendon length was 19 mm longer after nonsurgical treatment than after the surgical treatment of ATRs. These structural changes partly explained the 10% to 18% greater calf muscle strength observed in patients treated with surgery compared with those treated nonsurgically. Registration: NCT02012803 (ClinicalTrials.gov identifier).

A Retrospective Comparative Study With Historical Control to Determine the Effectiveness of Platelet-Rich Plasma as Part of Nonoperative Treatment of Acute Achilles Tendon Rupture

The aim of this study was to evaluate the effectiveness of platelet-rich plasma (PRP) in the nonoperative treatment of acute Achilles tendon rupture. This was a comparative study that included a prospective cohort and a historical control group. The control group was formed from a randomized trial in which one arm of the trial underwent nonoperative treatment, including accelerated functional rehabilitation after acute Achilles tendon rupture identical to that performed in the prospective treatment group. Patients in the prospective group were recruited consecutively and were administered 2 injections of PRP during the first 2 weeks after the injury. The primary outcome was isokinetic plantar flexion strength at 1 and 2 years after injury. Secondary outcomes included range of motion (ROM), calf circumference, and Leppilahti score. The ankle-hindfoot scale (American Orthopedic Functional Ankle Scale [AOFAS]) was administered to patients who received the PRP injection in the prospective group but was not measured for the historical group. A total of 73 patients participated in the prospective PRP study group and were compared with a retrospective control group of 72 patients from a previous randomized controlled trial (RCT). The mean difference between groups in isokinetic plantar flexion strength (injured/uninjured) at 1 year after injury was -4.3% (95% confidence interval [CI], -15.9 to 7.3; P = .5) and 2.4% (95% CI, -8.6 to 13.5; P = .7) at 30°/s and 60°/s, respectively. Results at 2 years after injury were -3.1% (95% CI, -13.5 to 7.2; P = .6) and 4.8% (95% CI, -3.5 to 13.1; P = .3) at 30°/s and 60°/s, respectively. All secondary outcomes were also not statistically different. The results of this study suggest that there is no measurable clinical benefit to the addition of PRP to the treatment regimen for nonoperatively treated acute Achilles tendon rupture. Level III, retrospective comparative study.

Operative Treatment of Chronic Irreparable Achilles Tendon Ruptures With Large Flexor Hallucis Longus Tendon Transfers

Transfer of the flexor hallucis longus (FHL) tendon aims to restore function and relieve pain in chronic Achilles tendon (AT) disease. The goal of the present study was to investigate the clinical and radiographic outcomes of FHL transfer to the AT and to compare the transtendinous technique to the transosseous technique. We hypothesized that the type of technique would have a notable impact on outcome. Forty patients (42 ankles) were retrospectively reviewed and divided into group 1 (transtendinous technique, 22 patients/24 ankles) and group 2 (transosseous technique, 18 patients/18 ankles). Outcome parameters included the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score, Victorian Institute of Sports Assessment-Achilles (VISA-A) score, Foot Function Index (FFI), and Short Form-36 (SF-36) scores. Magnetic resonance imaging of the lower leg was performed preoperatively to assess muscle quality and fatty infiltration. Postoperatively, isokinetic plantar flexion strength was assessed using a Con-Trex dynamometer. In group 1 (follow-up, 73 months; age, 52 years), the AOFAS score improved from 66 points to 89 points (P < .001) with average values for the VISA-A of 76 points, FFI-D pain 15%, and FFI-D function 22%. In group 2 (follow-up, 35 months; age, 56 years), the AOFAS score increased from 59 points to 85 points (P < .001) with mean values for the VISA-A 76 points, FFI-D pain 25%, and FFI-D function 24%. At follow-up, the average SF-36 score in group 1 was 66% and in group 2 was 77%. Isokinetic testing at 30 deg/s in group 1 revealed notable weakness in the operated ankle averaging 54.7 N·m (75% of normal), and in group 2 the average was 58.2 N·m (77% of normal). No statistically significant differences were found between the groups. The hypothesis was disproved. Both techniques for FHL transfer to AT, intratendinous and transosseous, provided good to excellent clinical and functional outcome in the treatment of irreparable AT disease. Level III, retrospective comparative series.

Function and Strength Following Gastrocnemius Recession for Isolated Gastrocnemius Contracture

Isolated gastrocnemius contracture (IGC), which limits ankle dorsiflexion with full knee extension, can affect function and quality of life. Gastrocnemius recession is a treatment option for IGC when conservative treatment fails. The goal of this study was to assess range of motion, function, and plantarflexion strength pre- and 3-months post-gastrocnemius recession for subjects with IGC. Ankle range of motion, function, and plantarflexion strength in seven legs (four subjects), clinically diagnosed with IGC, before and after surgery were compared to matched control subjects to elucidate pre- and post-surgical intervention differences. All subjects with IGC were also diagnosed with plantar fasciitis with one leg having an additional diagnosis of metatarsalgia. Subjects with IGC had significant post surgical improvements at 3 months after surgery in dorsiflexion range of motion (p = 0.016), function (p = 0.016) and isokinetic plantarflexion strength (p = 0.018). Surgical recession enhanced range of motion and self reported function while not inducing any detrimental effects to plantarflexion strength at a 3-month followup. Post-surgically IGC subjects were more similar to healthy controls.

Operative Versus Non-Operative Treatment of Achilles Tendon Ruptures: A Randomized Controlled Trial (SS-66)

The purpose of this randomized controlled trial was to compare outcomes of operative and non-operative management of Achilles tendon ruptures. Patients with acute complete Achilles tendon ruptures were randomized to receive open suture repair followed by graduated rehabilitation or graduated rehabilitation alone. The primary outcome measure was re-rupture rate. Assessments at 3 and 6 months, and 1 and 2 years included a modified Leppelhati score (no strength data), range of motion, calf circumference, and isokinetic strength at 1 and 2 years. We report the 2 year findings. Two centres randomized 145 patients (118 males and 27 females), mean age 40.9 ± 8.8 years (22.5 - 67.2) to operative (n=73) and non-operative (n=72) treatment. Fourteen were lost to follow-up. Re-rupture occurred in 3 patients in both groups. The mean modified Leppelhati score (out of 85) was 78.2 ± 7.7 in the operative group and 79.7 ± 7.0 in the non-operative group, which was not significant (-1.5 95%CI −6.4 to 3.5, p=0.55). Mean side-to-side difference in plantar flexion and calf-circumference in the operative group was −2.0 ± 3.2° and −1.4 ± 1.2cm, and in the non-operative group −0.9 ± 3.0°and −1.6 ± 1.8cm respectively. Mean isokinetic plantar flexion strength was 62.4 ± 24.2 for the operative and 56.7 ± 19.3 for the non-operative group, which was not significant (5.7, 95%CI −3.1 to 14.5, p=0.20). There were a greater number of serious adverse events in the operative group, including pulmonary embolus in 1 patient, deep vein thrombosis in 1 and deep infections requiring irrigation and debridement in 3. This study suggests that non-operative management of Achilles tendon ruptures utilizing an accelerated rehabilitation programme may produce comparable results with fewer adverse events.

Optimal Post-Training Abstinence for Maximal Strength Expression

Tapering commonly precedes strength/power competitions to augment performance, and training abstinence is an extreme manifestation of taper. This study compared the effects of different training-abstinence intervals on several indices of strength. Postresting strength performance was compared in 54 young men who had abstained from a standardized weight training program for either 2, 3, 4, or 5 days. Testing included 1RM heel raise strength and isokinetic plantar flexion peak torque at 1.05 and 3.14 rad · s-1. Heel raise strength was greater at 4 days as compared to 2 or 5 days, whereas performance at 3 days was no different (p > .05) than any of the other rest intervals. Isokinetic plantar flexion peak torque at both 1.05 and 3.14 rad · s-1 was unaffected by any of the rest intervals. Small to moderate effect sizes were found for heel raise strength for groups resting 3 and 4 days as well as for slow and fast isokinetic peak torque for the group resting 4 days. It was concluded that a transient elevation in heel raise strength in young men appears to occur by the fourth day of abstinence from heavy-resistance heel-raise training. Under the same experimental conditions, it appears that a modest increase in both slow and fast isokinetic plantar-flexion strength may also occur.

Rerupture and deep infection following treatment of total Achilles tendon rupture.

The incidence of total Achilles tendon rupture has increased, but we are not aware of any reports on the incidence of reruptures or deep infections following treatment. The outcome after successful treatment is good, but that after complications has not been well documented. A group of 409 patients with a complete Achilles tendon rupture was treated at a university hospital orthopaedic unit between 1979 and 2000. Twenty-three reruptures (prevalence, 5.6%) and nine deep infections (prevalence, 2.2%) occurred in twenty-nine patients. We retrospectively reviewed the records of these patients to determine the overall incidence of ruptures, reruptures, and deep infections and to record the known risk factors for these major complications. We analyzed the final clinical outcome for twelve patients with a rerupture and seven patients with a deep infection at a mean of 4.1 years after the initial treatment. The annual incidence of reruptures (per 100,000 inhabitants) increased from 0.25 in 1979-1990 to 1.0 in 1991-2000, and that of deep infections increased from 0 in the 1980s to 0.63 in the 1990s. The ratio of complications to primary ruptures did not change. The patients with deep infections were significantly older, received corticosteroid medication more often, had sustained the tendon injury during everyday activities more often, and had a longer delay before treatment than the patients with simple reruptures. At 4.1 years after the primary treatment, eight of twelve patients in the rerupture group had a satisfactory clinical outcome and the overall average isokinetic plantar flexion strength deficit in that group was only 10%. In contrast, two of the patients in the infection group had a fair clinical outcome and five had a poor outcome, and the average isokinetic plantar flexion strength deficit in that group was 35%. The incidence of Achilles tendon reruptures and deep infections has increased. The outcome is satisfactory after a simple rerupture without infection, but the results after a deep infection are often devastating.

Exercise Performance, Functional Status, and Hemodynamic Assessment of Elderly Patients with Intermittent Claudication

Peripheral arterial disease (PAD) is associated with impaired lower extremity function. This study investigated differences in PAD and control participants and the relationship between lower limb strength and clinical measures of PAD severity. Participants were evaluated by 6-min-walk distance, normal and maximal walking speed over 10 m, isometric plantar-flexion strength, and dynamic dorsi-/plantar-flexion strength. Hemodynamic measures of the lower limbs were recorded at rest and after maximal treadmill testing. PAD participants walked significantly less far during the 6-min walk, and there were large differences in normal and maximal walking speeds. Small to moderate differences were found for isometric plantar-flexion strength. In the diseased legs of the PAD participants, resting systolic hallux photoplethysmography was significantly correlated with isokinetic plantar-flexion strength and onset of claudication pain during the 6-min-walk test. In addition to confirming the documented loss of walking endurance, these data suggest that loss of strength of the plantar flexors is associated with increasing PAD impairment.

Comparison of Functional Ability Following Percutaneous and Open Surgical Repairs of Acutely Ruptured Achilles Tendons

The purpose of our study was to evaluate the functional outcomes of two methods of surgical treatment of acute closed raptures of the Achilles tendon, specifically, the primary open repair and the percutaneous repair techniques, utilizing (a) isokinetic plantar flexion strength, (b) midcalf girth, (c) ankle joint proprioception, and (d) ankle range of motion values. As a secondary purpose, the frequency of reruptures and postsurgical complications were compared between techniques. Twenty male patients (mean age, 43.8 ± 9.4 years) who sustained complete, closed ruptures of the Achilles tendon participated in this study. Results of pairedttests revealed significant differences between postsurgical and contralateral normal limbs for 6 of 12 variables. Results of the ANOVAs revealed no significant differences between the open repair group and percutaneous repair group for any of the evaluative parameters. The significant deficits in postoperative isokinetic plantar flexion strength and midcalf girth measurements, irrespective of surgical technique, suggest an incompleteness of rehabilitation or, more likely, the physiological inability to regain these characteristics postoperatively.

The Effect of Position and Speed on Ankle Plantarflexion in Females

This study was undertaken to determine isokinetic plantarflexion strength at various speeds and positions on a Cybex II+ dynamometer. A second purpose of this study was to identify any relationship between calf circumference and strength. Speeds used were 0, 30, and 180 degrees /sec. Positions used were supine with 0 degrees knee extension, supine with 90 degrees knee flexion, and prone with 0 degrees knee extension. Speeds and positions are randomly ordered. Nineteen female subjects were classified as either trained (N = 9) or untrained (N = 10). Plantarflexion strength was greatest in the supine position with 0 degrees knee extension in each of the three speeds tested. The results of a two-way repeated measures analysis of variance test were significant across all speeds occurring only with the trained group at a speed of 0 degrees /sec. Further comparisons of position with other speeds were not significant. Since plantarflexion torques were higher in the supine position with 0 degrees knee extension with a speed of 30 degrees /sec, clinicians might want to use this position and speed to test ankle plantarflexion torque. The relationship between calf circumference and torque was not significant. J Orthop Sports Phys Ther 1990;12(4):153-156.