Isokinetic Quadriceps Strength Research Articles

Determining Criteria to Predict Repeatability of Performance in Older Adults: Using Coefficients of Variation for Strength and Functional Measures.

Reliable measures of muscle strength and functional capacity in older adults are essential. The aim of this study was to determine whether coefficients of variation (CVs) of individuals obtained at the first session can infer repeatability of performance in a subsequent session. Forty-eight healthy older adults (mean age 68.6 ± 6.1 years; age range 60-80 years) completed two assessment sessions, and on each occasion undertook: dynamometry for isometric and isokinetic quadriceps strength, 6 meter fast walk (6MFWT), timed up and go (TUG), stair climb and descent, and vertical jump. Significant linear relationships were observed between CVs in session 1 and the percentage difference between sessions 1 and 2 for torque at 60, 120, 240 and 360°/s, 6MFWT, TUG, stair climb, and stair descent. The results of this study could be used to establish criteria for determining an acceptably reliable performance in strength and functional tests.

Femoral Nerve Block after Anterior Cruciate Ligament Reconstruction.

Femoral nerve block (FNB) has been proposed for pain control following anterior cruciate ligament (ACL) reconstruction. Although numerous studies have assessed the efficacy of FNBs, there has been little to no research into the effect of such blocks on postoperative strength and patient-reported outcomes. We hypothesized that performance of an FNB would result in decreased quadriceps strength and poorer patient-reported outcome scores within the first 6 months following ACL reconstruction. A total of 30 patients scheduled to undergo hamstring autograft ACL reconstruction following an acute ACL injury were randomized to a single-shot FNB group or a control group. Preoperatively, patients completed a Knee Injury and Osteoarthritis Outcome Score (KOOS) and isokinetic quadriceps strength testing at 60 degrees/second. At 6 weeks postoperative, 29 of 30 patients completed a KOOS and isometric quadriceps strength testing at 90 degrees. At 6 months postoperative, 23 of 30 patients completed a KOOS and isokinetic strength testing. Quadriceps femoris strength limb symmetry indices (QF-LSI) were calculated at all time points. Repeated measures analysis of variance (ANOVA) models were then utilized to model the effect of FNB and time on QF-LSI as well as KOOS subscales for activities of daily living, pain, and symptoms. QF-LSI and all KOOS subscales demonstrated improvement with time following ACL reconstruction. Repeated measures ANOVA demonstrated that patients who underwent FNB had a mean QF-LSI that was 13.4% lower than the control group (p = 0.005) and poorer KOOS symptoms subscale scores (10.4 point difference, p = 0.032) at 6 weeks postoperative compared with controls. At 6 months postoperative, no differences were noted in QF-LSI or any of the KOOS subscales based on block status. FNB resulted in decreased strength and poorer KOOS symptom subscale score at 6 weeks following ACL reconstruction compared with controls. These differences resolved by 6 months postoperative. The long-term effect of delayed quadriceps recovery on movement patterns and functional outcome remains unknown and requires further study. The study is a randomized controlled trial with level of evidence 1.

Changes in Neuromuscular Performance throughout the Menstrual Cycle in Physically Active Females

PURPOSE: The purpose of this study was to determine the change in neuromuscular performance throughout the menstrual cycle in college-aged females and the effect of hormonal contraception on these changes. METHODS: Fifty physically active college females (25 on oral contraceptives (OC)) were recruited to participate in three visits throughout one menstrual cycle. Visits coincided with the follicular (Fp), ovulatory (Op), and the luteal (Lp) phases. Blood was drawn at each visit to determine circulating concentrations of estradiol (E2), progesterone (P4), and relaxin (R2). Grip strength, knee joint laxity, q-angle, and isokinetic quadriceps strength at 60°/sec, 180°/sec, and 300°/sec were measured. Data were analyzed using linear mixed effect models taking into account repeated measures. RESULTS: Grip strength was lower during Fp (30.1 ± 0.7 kg/m2) than during Op (31.5 ± 0.7 kg/m2, p=0.003) and Lp (32.6 ± 0.7 kg/m2, p<0.001). Isokinetic peak torque (IPT) at 60°/sec was lower during Fp (112 ± 3 ft-lbs) than during the Op (116 ± 3 ft-lbs, p=0.009). IPT at 180°/sec was lower during the Fp (73 ± 2.0 ft-lbs) than the Op (79 ± 2 ft-lbs, p<0.001) and Lp (82 ± 2 ft-lbs, p<0.001). Results were similar for the 300°/sec isokinetic testing with lower peak torque during Fp (58 ± 2 ft-lbs) than the Op (63 ± 2 ft-lbs, p<0.001) or Lp (63 ± 2 ft-lbs, p<0.001). No differences were observed among any of the visits for knee joint laxity, or quadriceps angle. The OC-by-phase interaction was not significant for any of the outcomes or R2 concentration, but was significant for E2 and P4 with the concentrations of E2 and P4 being lower during the ovulatory and luteal phases in the OC group. Inclusion of E2, P4 or R2 in statistical models did not affect any of the outcomes for either group. CONCLUSION: Results indicate that muscular performance is diminished during follicular phase (menstruation) and the lack of significant OC-by-phase interaction indicates that this effect is not related to OC use, E2 concentrations, or P4 concentrations. Based on these data we postulate that female athletes may be at a greater risk of injury due to decreased strength during Fp than other phases of their cycle; future studies should focus on attenuating the strength decrease observed during menstruation.

Structural and Sensorimotor Deficits Associated with Abnormal Frontal Plane Motion of the Knee during Gait: The Multicenter Osteoarthritis Study

Varus knee thrust is a visible manifestation of excessive frontal plane knee motion (i.e., an abrupt change to varus knee alignment) during the mid‐stance phase of gait. Thrust is a potent mechanical risk factor for knee osteoarthritis (OA) progression and knee pain during weight bearing. Given the association of thrust with knee disease, determining the underlying causes of thrust could facilitate the development of strategies for early detection and prevention. These causes may be related to sensorimotor deterioration and may include impairments in afferent sensory input or efferent muscular strength. Alternatively, knee thrust could result from structural anomalies, such as static knee malalignment or instability (passive laxity) of the knee joint. Our objective was to determine associations between these sensorimotor and structural deficits and the presence of varus knee thrust in older adults that are at risk for knee OA. The Multicenter Osteoarthritis Study (MOST) is a longitudinal prospective cohort study of older Americans that have or are at risk for knee OA. Participants’ gait was recorded (via 60 Hz video) during two self‐paced walking trials on a 4.9 meter walkway. A trained video reader blinded to knee disease status assessed the presence of varus thrust on a majority of steps (κ = 0.73). Static knee alignment measures were obtained using full‐limb radiographs; passive varus knee joint laxity was measured as varus excursion following the application of a fixed load; isokinetic quadriceps strength was measured as the maximal torque produced over four trials; lower extremity vibration perception threshold was measured using a biothesiometer and defined as the voltage at which a subject first sensed vibration; and knee joint position sense was measured as the average error between ten preset and participant‐reproduced knee flexion angles. Using separate logistic regression models, we assessed the cross‐sectional relationship between varus thrust and increasing levels of each structural and sensorimotor exposure, accounting for non‐independence between two knees from the same subject and adjusting for age, sex, body mass index (BMI), and walking velocity. Our sample consisted of 1877 persons (age 66.69 ± 7.51, BMI 29.47 ± 4.75, 62.5% female) contributing 3730 knees. Varus thrust was observed in 31.3% of knees. Static varus alignment (&lt; 179º) was most strongly associated with varus thrust (OR 2.39, 95% CI 1.96, 2.92), while increasing varus knee joint laxity had a surprising protective effect (p for trend = 0.0006). After adjusting for confounders, none of the sensorimotor deficits examined were significantly associated with thrust. These results suggest that varus thrust during walking occurs within the context of static varus knee malalignment and that knee laxity may be correlated with a decreased risk of thrust in at‐risk older adults.Support or Funding InformationThe current study was funded in part by a Rheumatology Research Foundation Health Professional Research Preceptorship Award. MOST is funded by the National Institutes of Health National Institute on Aging (Felson ‐ U01 AG18820, Lewis ‐ U01 AG18947, Torner ‐ U01 AG18832, Nevitt ‐ U01 AG19069). Relative Odds of Varus Knee Thrust with Increasing Exposure to Structural or Sensorimotor Impairments Structural Impairments Static Knee Alignment Mechanical Angle (Degrees) n/N† Adjusted OR‡ (95%CI) 160.0 – 178.9# (Varus) 747/1839 2.39 (1.96, 2.92)# 179.0 – 181.0# (Neutral) 162/768 1.00 (ref) 181.1 – 195.4# 131/720 0.90 (0.70, 1.16) Varus Knee Laxity Varus Excursion (Degrees) n/N† Adjusted OR‡ (95%CI) 0.00 – 1.00# (Least Lax) 432/1168 1.00 (ref) 1.25 – 2.00# 265/905 0.74 (0.61, 0.89)# 2.25 – 3.00# 247/837 0.73 (0.60, 0.90)# 3.25 – 11.00# (Most Lax) 215/781 0.69 (0.56, 0.85)# p for Trend ‐‐‐ 0.0006# Sensorimotor Impairments Isokinetic Quadriceps Strength (Sex‐Specific Quartiles) Maximum Torque (Nm) n/N† Adjusted OR‡ (95%CI) F:84 – 149/M: 145 – 253 (Strongest) 142/474 1.00 (ref) F: 68 – 83/M: 117 – 144 142/477 0.74 (0.52, 1.05) F: 51 – 67/M 91 – 115 197/616 0.78 (0.58, 1.05) F: 7 – 50/M: 9 – 90 86/360 0.87 (0.65, 1.16) p for Trend ‐‐‐ 0.07 Knee Joint Position Sense Average Error (Degrees) n/N† Adjusted OR‡ (95%CI) 0.6 – 2.9# (Least Deficit) 238/817 1.00 (ref) 3.0 – 3.9# 242/780 1.14 (0.87, 1.50) 4.0 – 5.2# 245/749 1.17 (0.89, 1.54) 5.3 – 13.8# (Greatest Deficit) 252/774 1.18 (0.90, 1.52) p for Trend ‐‐‐ 0.25 Vibration Perception Perception Threshold (Volts) n/N† Adjusted OR‡ (95%CI) 2.50 – 13.50 (Least Deficit) 207/805 1.00 (ref) 13.75 – 19.25 244/811 1.12 (0.91, 1.37) 19.50 – 28.75 270/826 1.08 (0.88, 1.33) 29.00 – 51.00 (Greatest Deficit) 330/818 1.17 (0.94, 1.46) p for Trend ‐‐‐ 0.24 number of knees with thrust/Number of knees analyzed Adjusted for age, sex, BMI, and walking velocity Results are Significant at the 0.05 level

Influence of Anterior Cruciate Ligament Tear on Thigh Muscle Strength and Hamstring-to-Quadriceps Ratio: A Meta-Analysis.

Theoretical compensation after anterior cruciate ligament (ACL) tear could cause quadriceps weakness and hamstring activation, preventing anterior tibial subluxation and affecting the expected hamstring-to-quadriceps ratio. Although quadriceps weakness often occurs after ACL tears, it remains unclear whether hamstring strength and hamstring-to-quadriceps ratio increase in ACL deficient knees. This meta-analysis compared the isokinetic muscle strength of quadriceps and hamstring muscles, and the hamstring-to-quadriceps ratio, of the injured and injured limbs of patients with ACL tears. This meta-analysis included all studies comparing isokinetic thigh muscle strengths and hamstring-to-quadriceps ratio in the injured and uninjured legs of patients with ACL tear, without or before surgery. Thirteen studies were included in the meta-analysis. Quadriceps and hamstring strengths were 22.3 N∙m (95% CI: 15.2 to 29.3 N∙m; P<0.001) and 7.4 N∙m (95% CI: 4.3 to 10.5 N∙m; P<0.001) lower, respectively, on the injured than on the uninjured side. The mean hamstring-to-quadriceps ratio was 4% greater in ACL deficient than in uninjured limbs (95% CI: 1.7% to 6.3%; P<0.001). Conclusively, Decreases were observed in both the quadriceps and hamstring muscles of patients with ACL tear, with the decrease in quadriceps strength being 3-fold greater. These uneven reductions slightly increase the hamstring-to-quadriceps ratio in ACL deficient knees.

Comparison between Isokinetic Quadriceps and Hamstring Strength and Clinical Outcomes after Single Bundle and Double Bundle ACL Reconstruction in Sportspersons

Existing studies suggest the advantage of rotational stability in DB ACL over SB ACL. However, the contribution of strength parameters need to be evaluated further. Muscle strength deficiet is one of the consequences after ACL reconstruction. The aim of this study was to evaluate any possible differences in isokinetic hamstring and quadriceps muscle strength and functional outcome after SB and DB ACL Reconstruction in sportspersons. We tested 30 sportspersons (15 SB and 15 DB) after primary reconstruction of ruptured anterior cruciate ligament at angular velocities of 60°/second and 120°/second using isokinetic dynamometer, functional testing was done using lysoholm and IKDC score. Overall, there was statistically significant difference in flexion and extension strength parameters at 60°/sec as compared to 120°/second in both SB and DB groups. there was no significant difference in isokinetic strength of quadriceps and hamstrings between SB and DB groups. Clinical evaluation done by lysoholm and IKDC score also showed no significant difference. However, in both groups maximal muscle strength is more than muscle endurance.

Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial.

Protein supplementation in combination with resistance training may increase muscle mass and muscle strength in elderly subjects. The objective of this study was to assess the influence of post-exercise protein supplementation with collagen peptides v. placebo on muscle mass and muscle function following resistance training in elderly subjects with sarcopenia. A total of fifty-three male subjects (72·2 (sd 4·68) years) with sarcopenia (class I or II) completed this randomised double-blind placebo-controlled study. All the participants underwent a 12-week guided resistance training programme (three sessions per week) and were supplemented with either collagen peptides (treatment group (TG)) (15 g/d) or silica as placebo (placebo group (PG)). Fat-free mass (FFM), fat mass (FM) and bone mass (BM) were measured before and after the intervention using dual-energy X-ray absorptiometry. Isokinetic quadriceps strength (IQS) of the right leg was determined and sensory motor control (SMC) was investigated by a standardised one-leg stabilisation test. Following the training programme, all the subjects showed significantly higher (P<0·01) levels for FFM, BM, IQS and SMC with significantly lower (P<0·01) levels for FM. The effect was significantly more pronounced in subjects receiving collagen peptides: FFM (TG +4·2 (sd 2·31) kg/PG +2·9 (sd 1·84) kg; P<0·05); IQS (TG +16·5 (sd 12·9) Nm/PG +7·3 (sd 13·2) Nm; P<0·05); and FM (TG -5·4 (sd 3·17) kg/PG -3·5 (sd 2·16) kg; P<0·05). Our data demonstrate that compared with placebo, collagen peptide supplementation in combination with resistance training further improved body composition by increasing FFM, muscle strength and the loss in FM.

Do Moments and Strength Predict Cartilage Changes after Partial Meniscectomy?

Higher knee load and quadriceps weakness are potential factors involved in the pathogenesis of knee osteoarthritis after arthroscopic partial meniscectomy (APM). In people following APM, this study evaluated the association between external knee joint moments and quadriceps strength and 2-yr change in indices of cartilage integrity in the medial tibiofemoral compartment and patella. Seventy people with medial APM were assessed 3 months after APM (baseline) and reassessed 2 yr later (follow-up). At baseline, isokinetic quadriceps strength and the external knee adduction moment (peak and impulse) and knee flexion moment (peak) during walking were assessed. Magnetic resonance imaging was used to assess cartilage (cartilage volume and cartilage defects) in the medial tibial compartment and patella at baseline and follow-up. Increased peak knee adduction moment during fast-pace walking at baseline was associated with onset or deterioration of medial tibiofemoral cartilage defects (OR, 2.06; 95% CI, 1.03-4.12; P = 0.042) over 2 yr. Increased peak knee flexion moment during normal-pace walking at baseline was associated with loss of patellar cartilage volume over 2 yr (β = -0.24; 95% CI, -0.47 to -0.01; P = 0.04). No significant association was observed for quadriceps strength. In middle-age adults, a higher peak knee adduction moment and peak knee flexion moment at 3 months after medial APM may be associated with adverse structural changes at the medial tibia and patella over the subsequent 2 yr. These preliminary findings warrant further investigation as interventions aimed at reducing these moments may be designed if appropriate.

Effect of exercise therapy compared with arthroscopic surgery on knee muscle strength and functional performance in middle-aged patients with degenerative meniscus tears: a 3-mo follow-up of a randomized controlled trial.

The aim of this study was to compare the effect of a 12-wk exercise therapy program and arthroscopic partial meniscectomy on knee strength and functional performance in middle-aged patients with degenerative meniscus tears. A total of 82 patients (mean age, 49 yrs; 35% women) with a symptomatic, unilateral, magnetic resonance imaging-verified degenerative meniscus tear and no or mild radiographic osteoarthritis were randomly assigned to a supervised neuromuscular and strength exercise program or arthroscopic partial meniscectomy. Outcomes assessed 3 mos after intervention initiation were isokinetic knee muscle strength, lower extremity performance, and self-reported global rating of change. Mean difference in isokinetic knee extension peak torque between the two groups was 16% (95% confidence interval, 7.1-24.0) (P < 0.0001), favoring the exercise group. Patients in the exercise group improved isokinetic knee extension peak by a mean of 25 Nm (range, 18-33 Nm) from baseline to follow-up. Furthermore, patients assigned to exercise therapy showed statistically significant improvements (P ≤ 0.002) in all other measured variables, with moderate to large effect sizes (0.5-1.3). Patients reported a similar and positive effect of both interventions. A 12-wk supervised exercise therapy program yielded clinically relevant and statistically significant improvement in isokinetic quadriceps strength immediately after completion of the program, as compared with treatment with arthroscopic partial meniscectomy.

The relationship between quadriceps strength and joint position sense, functional outcome and painful activities in patellofemoral pain syndrome.

The aim of this study was to investigate how strongly the concentric and eccentric quadriceps strengths were correlated with the joint position sense, functional outcomes and painful activities in patients with patellofemoral pain syndrome (PFPS). The study included forty-six women diagnosed with unilateral PFPS. Eccentric and concentric quadriceps strengths were recorded at 60 and 180°/s. Active knee joint position sense (JPS) was measured at 20° and 60° of flexion. Functional levels were determined by using Kujala patellofemoral scores. Pain levels during stair descending and ascending, squatting and prolonged sitting were measured using 0-10cm visual analogue scale. The relationship of isokinetic quadriceps strength with JPS results, Kujala score and pain levels were evaluated using Spearman's correlation coefficient test. Eccentric and concentric quadriceps strengths were significantly lower on involved side than uninvolved side. JPS results were poorer on the painful knee when compared to uninvolved side. While eccentric strength correlated with both JPS target angles, concentric strength was correlated only with 20°. Both eccentric and concentric strengths were significantly correlated with Kujala scores and pain levels. Quadriceps eccentric strength was correlated more to joint position sense than concentric strength. Both eccentric and concentric quadriceps strength related to pain and functional level in PFPS patients.

Hamstrings strength imbalance in professional football (soccer) players in Australia.

The aim of this study was to describe the isokinetic thigh muscle strength profile of professional male football players in Australia. Concentric (60° and 240°·s(-1)) and eccentric (30° and 120°·s(-1)) hamstrings and quadriceps isokinetic strength was measured with a HUMAC NORM dynamometer. The primary variables were bilateral concentric and eccentric hamstring and quadriceps peak torque ratios, concentric hamstring-quadriceps peak torque ratios, and mixed ratios (eccentric hamstring 30°·s(-1) ÷ concentric quadriceps 240°·s(-1)). Hamstring strength imbalance was defined as deficits in any 2 of: bilateral concentric hamstring peak torque ratio <0.86, bilateral eccentric hamstring peak torque ratio <0.86, concentric hamstring-quadriceps ratio <0.47, and mixed ratio <0.80. Fifty-five strength tests involving 42 players were conducted. Ten players (24%) were identified as having hamstring strength imbalance. Athletes with strength imbalance had significantly reduced concentric and eccentric bilateral hamstring peak torque ratios at all angular velocities tested; and reduced eccentric quadriceps peak torque (30°·s(-1)) in their stance leg, compared with those without strength imbalance. Approximately, 1 in 4 players had preseason hamstring strength imbalance; and all strength deficits were observed in the stance leg. Concentric and eccentric hamstrings strength imbalance may impact in-season football performance and could have implications for the future risk of injury.

Does the length of incision in the quadriceps affect the recovery of strength after total knee replacement?

We have compared the time to recovery of isokinetic quadriceps strength after total knee replacement (TKR) using three different lengths of incision in the quadriceps. We prospectively randomised 60 patients into one of the three groups according to the length of incision in the quadriceps above the upper border of the patella (2 cm, 4 cm or 6 cm). The strength of the knees was measured pre-operatively and every month post-operatively until the peak quadriceps torque returned to its pre-operative level. There was no significant difference in the mean operating time, blood loss, hospital stay, alignment or pre-operative isokinetic quadriceps strength between the three groups. Using the Kaplan-Meier method, group A had a similar mean recovery time to group B (2.0 ± 0.2 vs 2.5 ± 0.2 months, p = 0.176). Group C required a significantly longer recovery time (3.4 ± 0.3 months) than the other groups (p < 0.03). However, there were no significant differences in the mean Oxford knee scores one year post-operatively between the groups. We conclude that an incision of up to 4 cm in the quadriceps does not delay the recovery of its isokinetic strength after TKR.

The Effect of Femoral Nerve Block on Strength and Patient-reported Outcomes Following ACL Reconstruction

Objectives:Femoral nerve block (FNB) has been proposed for pain control following anterior cruciate ligament (ACL) reconstruction. Although numerous high level studies have assessed the efficacy of FNB’s, there has been little to no research into the effect of such blocks on post-operative strength and patient-reported outcomes. Exacerbation of post-operative quadriceps weakness by a FNB could negatively impact recovery, particularly in the early post-operative period. We hypothesized that performance of a FNB would result in decreased quadriceps strength and poorer patient-reported outcome score in the first three months following ACL reconstruction.Methods:Thirty patients scheduled to undergo hamstring autograft ACL reconstruction following an acute ACL injury were randomized to a single shot FNB group or a control group. The surgical procedure and post-operative rehabilitation were performed identically in both groups. Pre-operatively, all patients completed a KOOS and isokinetic quadriceps strength testing at 60 deg/s. At 6 weeks post-operative, all patients completed a KOOS and isometric quadriceps strength testing at 90 deg. At 12 weeks post-operative, all patients but three completed a KOOS and isokinetic strength testing. Quadriceps strength limb symmetry indices (LSI) were calculated at all time points by dividing the strength of the involved limb by the strength of the uninvolved limb. LSI and KOOS subscales for Activities of Daily Living (ADL), Pain, and Symptoms at 6 weeks and 12 weeks were compared with pre-operative values.Results:Patients who underwent nerve block demonstrated a significant decrease in their LSI from pre-operative (0.80 ± 0.14) to 6 weeks post-operative (0.67 ± 0.29) (p = 0.05). Patients who did not undergo nerve block demonstrated no significant difference in the pre-operative (0.77 ± 0.23) and 6-week post-operative (0.78±0.28) LSI (p = 0.99). At 12 weeks post-operative, both groups demonstrated LSI values that were not statistically different from pre-operative. Patients who had a FNB demonstrated no change in their KOOS subscales from pre-op to 6 weeks post-op, while those patients who did not undergo FNB demonstrated a statistically significant increase in KOOS ADL, pain, and symptoms subscales from pre-operative to 6 weeks post-operative (Figure 1). All patients, regardless of group, demonstrated significant increases in KOOS subscales at 12 weeks relative to pre-operative (Figure 1).Conclusion:Femoral nerve block is associated with decreased quadriceps strength at 6 weeks post-operative, slowing the post-operative improvement in patient-reported outcome scores. While strength returns to pre-operative levels at 12 weeks post-operative, the effect of early quadriceps weakness on movement patterns and functional outcome at later time points has yet to be determined.

Individualized physiotherapy in the treatment of patellofemoral pain.

Patellofemoral pain (PFP) is associated with a wide range of local and global physical factors possibly contributing to pain and thus requires detailed assessment and individualized treatment. Yet, no cohort study was found that assessed the value of individualized physiotherapy, probably because this approach lends itself to clinical practice but not to scientific research. Most studies focus on a 'knee' or 'hip' treatment approach irrespective of individual global differences in lower limb alignment, movement patterns and muscle tightness. Therefore, this study aimed to determine the effectiveness of supplementing local treatment of PFP with individualized treatment targeting global contributing factors. Secondarily it aimed to subgroup the patients according to variations in lower limb alignment/laxity, movement patterns, biarticular muscle tightness and joint degeneration. Forty-one patients (60 knees) with PFP who had followed a programme of local quadriceps strengthening, quadriceps stretching and taping for one fortnight were prescribed an individualized programme based on assessment. This global assessment included lower limb postural alignment, movement patterns, muscle tightness and range of motion. Another fortnight's treatment was prescribed accordingly and included specific, individualized postural and movement retraining, stretching and functional weight-bearing, strengthening exercises. Seven outcome measures, namely four pain measures, isokinetic quadriceps strength, quadriceps length and eccentric knee control, assessed improvement. All outcome measures showed further significant improvement following individualized treatment (p < 0.03). Patients fell into four broad physical subgroups: hypermobility (often with malalignment), hypomobility (with three of four tight muscle groups), faulty movement patterns (mostly dynamic knee valgus) and patellofemoral osteoarthritis. Individualized treatment supplementing local standard physiotherapy for PFP leads to further significant improvement over 2 weeks. This study highlights the importance of assessing patients globally in order to optimize treatment and ongoing improvement. Recognition of different subgroups may guide treatment that should include both local and deficit-targeted global treatment.

CSM 2014 Sports Physical Therapy Section Platform Presentations (Abstracts SPL1–SPL66)

CSM 2014 Sports Physical Therapy Section Platform Presentations (Abstracts SPL1–SPL66)

Does the Length of Quadriceps Incision Affect the Recovery of Isokinetic Quadriceps Strength After Minimally Invasive Total Knee Arthroplasty: A Prospective Randomized Clinical Trial

This study demonstrated that more than 4 cm of quadriceps incision caused the delayed recovery time of isokinetic quadriceps strength after MIS-TKA. Minimally invasive surgical (MIS) techniques are proposed in order to minimize the disruption of quadriceps mechanism after total knee arthroplasty (TKA). Although the loss of quadriceps strength and its return has been investigated extensively, none of the studies has focused on the effect of the length of quadriceps incision on its strength recovery. This study thus aimed to use an isokinetic muscle testing to objectively evaluate the time that the quadriceps strengths return to their preoperative status after MIS-TKA among the three different lengths of quadriceps incisions. Sixty patients who underwent unilateral MIS-TKA using mini-medial parapatellar technique were prospectively randomized into one of the three groups, according to the length of quadriceps incisions from upper pole of patella: group A or <2 cm (20 knees), group B or 2-4 cm (20 knees) and group C or >4 cm (20 knees). The isokinetic strengths of the quadriceps were assessed preoperatively and every month postoperatively until the peak torque of quadriceps strength returned to their preoperative status. Times to quadriceps strength recovery and perioperative data were compared among the three groups. Patients’ characteristics and perioperative data, including operative time, blood loss and hospital stay, were comparable among the three groups. There was also no significant difference in preoperative isokinetic quadriceps strengths (28.5 ± 10.7, 33.2 ± 19.8 and 34.5 ± 12.8 Nm for group A, B and C respectively, p = 0.646). By using the Kaplan Meier method, the median times to recovery in Group A and B were 2 months. Group C used significantly more recovery time (3 months) than the other group (p = 0.002). No other complications were detected in this study. This study demonstrated that more than 4 cm of quadriceps incision caused the delayed recovery time of isokinetic quadriceps strength after MIS-TKA.

The relationship between quadriceps muscle weakness and worsening of knee pain in the MOST cohort: a 5-year longitudinal study

To determine whether quadriceps weakness is associated with elevated risk of worsening knee pain over 5 years. The Multicenter Osteoarthritis Study (MOST) is a longitudinal study of 50-79-year-old adults with knee osteoarthritis (OA) or known risk factors for knee OA. The predictor variable was baseline isokinetic quadriceps strength. Covariates included baseline body mass index (BMI), physical activity level, and history of knee surgery. The outcome was worsening pain reported on the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index pain subscale or knee replacement surgery between baseline and 5-year follow-up. Analyses were knee-based and used generalized estimating equations, stratified by sex to assess whether the lowest compared with the highest tertile of baseline quadriceps strength was associated with an increased risk of worsening knee pain at 5-year follow-up, controlling for age, BMI, history of knee surgery, and physical activity level as well as correlation between knees within participants. Analyses of worsening knee pain included 4,648 knees from 2,404 participants (61% female). Men with lower quadriceps strength did not have a higher risk of worsening knee pain (RR {95% CI}=1.01 {0.78-1.32}, P=0.9183). However, women in the lowest compared with the highest strength tertile had a 28% increased risk of worsening knee pain (RR {95% CI}=1.28 {1.08-1.52}, P=0.0052). Quadriceps weakness was associated with an increased risk of worsening of knee pain over 5 years in women, but not in men.

Relationship between muscle mass and muscle strength, and the impact of comorbidities: a population-based, cross-sectional study of older adults in the United States

BackgroundLoss of muscle mass and muscle strength are natural consequences of the aging process, accompanied by an increased prevalence of chronic health conditions. Research suggests that in the elderly, the presence of comorbidities may impact the muscle mass/strength relationship. The objectives of this study were to characterize the muscle mass/strength relationship in older adults in the USA and to examine the impact of a variety of comorbidities on this relationship.MethodsData were obtained from the National Health and Nutrition Examination Survey 1999–2002 databases. Subjects aged 50 years and older were included in the present study. Muscle mass was assessed by height-adjusted appendicular skeleton muscle mass (aASM) in kg/m2, as measured by dual-energy x-ray absorptiometry. Muscle strength was assessed via isokinetic quadriceps strength (IQS) in newton as measured by a dynamometer. The relationship between aASM and IQS was assessed adjusting for age and gender. The effects of a variety of comorbidities on IQS and/or on the relationship between IQS and aASM were assessed using multiple regression models.ResultsThis study included 2,647 individuals, with a mean age of 62.6 years and 52.9% of whom were female. The mean (SE) aASM (kg/m2) was 7.3 (0.04), and the mean (SE) IQS (newton) was 365.0 (3.00). After adjusting for age and gender, the correlation coefficient between aASM and IQS was 0.365 (P < 0.001). Diabetes, coronary heart disease/congestive heart failure (CHD/CHF), and vision problems were significant predictors of lower muscle strength (P < 0.05) in the multiple regression models that adjusted for age, gender, and aASM, and obesity significantly modified the relationship between aASM and IQS (P < 0.05).ConclusionsAmong individuals aged 50 and older in the US, muscle mass and muscle strength are positively correlated, independent of the associations of age and gender with muscle mass and strength. A variety of comorbid medical conditions serve as independent predictors of lower muscle strength (e.g., diabetes, CHD/CHF, vision problems) and/or modify the relationship between muscle mass and muscle strength (e.g., obesity).

ISOKINETIC STRENGTH AND RATIO OF PROFESSIONAL FOOTBALL PLAYERS IN UAE

Numerous research studies examined muscles strength among professional football players worldwide. However, little or no research studies exist on this issue with relation to Arabian Gulf players. Therefore, the purpose...

Weak associations between structural changes on MRI and symptoms, function and muscle strength in relation to knee osteoarthritis

To explore associations between MRI-defined structural abnormalities and clinical features related to knee osteoarthritis (OA). Structural and clinical knee OA features were assessed in 87 women (45 with knee OA symptoms). Structural features were quantified by the Kellgren and Lawrence grade on radiography and by the Boston-Leeds Osteoarthritis Knee Score on MRI. Clinical features were assessed using the Knee Injury and Osteoarthritis Outcome Score, functional tests and muscle strength measurements. Associations were examined using regression analyses. Limited significant associations between structural and clinical features were found. An increased meniscal signal was associated with more pain/symptoms (P<0.027). An anterior cruciate ligament tear was associated with poorer stair climbing test performance (P=0.045). In a stepwise linear regression model, patellofemoral cartilage integrity and pain explained 28% of the isometric quadriceps strength variability. The amount of cartilage lesions, loose bodies and pain explained 38% of the isokinetic quadriceps strength variability. Synovitis/effusion and patellofemoral cartilage integrity combined with pain explained 34% of the isometric hamstring strength variability. Although MRI-detected cartilage lesions, synovitis/effusion and loose bodies did explain part of the muscle strength variability, results suggest that MRI does not improve the link between joint degeneration and the clinical expression of knee OA. MRI contributes less than expected to the understanding of pain and function in knee OA and possibly offers little opportunity to develop structure-modifying treatments in knee OA that could influence the patient's pain and function. Case series with no comparison groups, Level IV.