Weight-bearing Index Research Articles

Alleviating Effect of a Flower Extract of Styphnolobium japonicum L. on Symptoms of Experimentally Induced Osteoarthritis in Rats

In the present study, we prepared an ethanol extract from the flowers of Styphnolobium japonicum L. (SJFE) and found that it contains rutin as a major constituent as well as quercetin kaempferol and isorhamnetin as minor components. In lipopolysaccharide-stimulated RAW 264.7 macrophages, we observed that SJFE significantly inhibited the production of nitric oxide and the expression of major inflammatory biomarkers such as inducible NO synthase, cyclooxygenase-2, interleukin (IL)-6, and IL-1β significantly. Based on these in vitro results, we investigated the anti-inflammatory properties of SJFE on osteoarthritis (OA) of the left hind knee joints induced by monosodium iodoacetate in rats. SJFE was orally administered to the rats with arthritis for 4 weeks, and the following results were obtained. The rats treated with SJFE exhibited a 24% improvement in the weight-bearing index of their affected legs, as well as reductions of 31.5% and 23.2% in serum levels of cartilage oligomeric matrix protein and C-terminal telopeptide 2, respectively. Additionally, Mankin’s score, an indicator used to assess the severity of joint cartilage damage, decreased by 2.75 points compared to the control with no treatment. These findings suggest that SJFE possesses anti-inflammatory properties and can alleviate symptoms of OA, indicating its potential to offer relief to individuals suffering from arthritis.

EARLY EXPERIENCE OF THE FITBONE NAIL IN ADOLESCENCE: A LEARNING CURVE

IntroductionIntramedullary lengthening devices have been in use in older children with closed /open growth plates with good success. This study aims to present the early experience of the FITBONE nail since withdrawal of the PRECICE nail.Materials & MethodsRetrospective analysis of both antegrade and retrograde techniques were utilized. Only patients where union was achieved and full weight bearing commenced were included. The complication rate, length gained, distraction index, weight bearing index (WBI) as well as mechanical axes were analysed.Results14 (7 males, 7 females) of a total of 16 (7 males, 7 females) patients with a mean age of 16.9 years with varied diagnosis of LLD were analysed. The mean length gained was 38 mm with an average distraction index of 0,74 mm/day. WBI in these patients on average was 59,6 days/cm lengthened. 6 complications were observed, including two nonunions (successfully treated) and a knee subluxation. Mechanical axis deviation improved from 13,3 mm to 6 mm on average. Overall there has been a nonsignificant tendency for WBI to decrease (Spearman's rank correlation coefficient −0.47, p=0.08) with increasing number of cases done, while no correlation between length gained and WBI (−0.01, p=0.96, respectively) was observed. Some nuances will be discussed.ConclusionsLimb lengthening with the FITBONE nail is relatively safe and efficient, however no significant change was seen in the outcome with previous motorized nails.

Examination of Changes in 6-minute Walk Distance and Related Factors in Patients with Perioperative Peripheral Arterial Disease.

This study aimed to clarify the effects of pre- and postoperative physical function on the 6-minute walking distance (6MWD) in patients with peripheral arterial disease (PAD). Forty-two elderly patients with PAD who were hospitalized for revascularization and able to walk independently were included in the study. The 6MWD, ankle brachial index (ABI), weight-bearing index (WBI), gait, and intermittent claudication distance (ICD) were measured before and after the surgery, and skeletal muscle index was measured only before surgery. Analyses were performed by comparing the pre- and postoperative values of each factor using a paired t-test. In addition, multiple regression analysis was performed with 6MWD as the dependent variable before and after surgery. Postoperatively, pain disappeared in 22 patients, and ABI, ICD, 6MWD, and stride length improved significantly. ICD and stride length were extracted as factors related to 6MWD before and after surgery, and ABI, WBI, and stride length were extracted as factors related to 6MWD after surgery. The improvement of intermittent claudication associated with revascularization suggests a stronger influence of functional aspects on postoperative 6MWD.

Limb Lengthening With Precice Intramedullary Lengthening Nails in Children and Adolescents.

The Precice intramedullary bone lengthening nail has been used in our department since 2013. We sought to determine the efficacy and safety of intramedullary limb lengthening with Precice nails in children and adolescents. We retrospectively investigated patients 18 years and younger who underwent lower-limb lengthening using the Precice nail. Radiologic and clinical outcome data were obtained from a prospective database. The minimum postimplantation follow-up was 12 months. Between March 2013 and March 2020, 161 patients underwent limb lengthening with a Precice nail; 76 patients met the inclusion criteria. We used 84 nails in 76 patients (68 femurs and 16 tibias). Femoral nails were inserted using an antegrade approach in 57 patients and a retrograde approach in 11. The mean age at surgery was 16 years (range, 9 to 18 y). The mean lengthening was 33 mm (range, 14 to 80 mm) with additional acute axial or rotational malalignment correction in 16 segments. At the last follow-up (mean=2.1, years; range, 1 to 5 y), all regenerates had healed and all patients were mobile with full weight-bearing. Complications that necessitated surgical revision occurred in 6 patients (8%), and the desired lengthening was not achieved in 2 patients. Postlengthening malalignment occurred in 4 patients (5 tibial nails). The weight-bearing index, defined as days from surgery to full weight-bearing/cm of lengthening, was a mean of 45 days (range, 7 to 127 d/cm). The Precice nail facilitated reliable and safe bone lengthening and was associated with a low complication rate. Correction of additional malalignment was possible by applying intraoperative acute correction or guided growth. Level IV-therapeutic study investigating the results of treatment.

Complications and Effectiveness of Intramedullary Limb Lengthening: A Matched Pair Analysis of Two Different Lengthening Nails

BackgroundIntramedullary limb lengthening has become an accepted concept in reconstructive surgery, but as yet comparative clinical studies are missing. We compared the complications and effectiveness of two types of intramedullary limb lengthening devices (ISKD®; Fitbone®).Materials and methodsIn a retrospective series of 278 consecutive patients with internal limb lengthening, we found 17 matching pairs in terms of predefined matching parameters (group I with ISKD® and group II with Fitbone®). The surgeries were all performed with the same technique and managed with equivalent pre- and postoperative treatment protocols. The performance of the implants was evaluated using the distraction index and the weight-bearing index. Complications were rated according to Paley's classification for external lengthening.ResultsThe distraction index in group I (ISKD®) was 0.99 mm/day (range 0.55–1.67) and in the group II (Fitbone®) 0.55 mm/day (range 0.14–0.92) (p value = 0.001). The mean weight-bearing index differed between group I and group II from 32.0 day/cm (range 16.4–64.0) to 51.6 day/cm (25.8–95.0) (p value = 0.001). There were 17 recorded incidents in group I and 19 in group II during lengthening.ConclusionSpecific technical handicaps of the two systems, such as the so-called runaway of the ISKD® and backtracking of the Fitbone® nails seem to result in different distraction index and weight-bearing index. Further comparative studies might induce technical progress in intramedullary limb lengthening.How to cite this articleThaller PH, Frankenberg F, Degen N, et al. Complications and Effectiveness of Intramedullary Limb Lengthening: A Matched Pair Analysis of Two Different Lengthening Nails. Strategies Trauma Limb Reconstr 2020;15(1):7–12.

Association between locomotive syndrome and blood parameters in Japanese middle-aged and elderly individuals: a cross-sectional study

BackgroundLocomotive syndrome (LS) is associated with weakness and loss of function in the musculoskeletal organs. We aimed to determine the association between LS components and blood parameters in middle-aged and elderly individuals.MethodsWe included 223 middle-aged and elderly individuals in this study (104 men and 119 women; age: 40–85 years). All participants were asked to fast for at least 3 h before the venous blood samples were obtained and the hemoglobin, total protein, glycated hemoglobin (HbA1c), growth hormone, albumin and lipid profile were measured. Three functional tests, the stand-up test, the two-step test, and the 25-question geriatric locomotive function scale (GLFS) were used to assess the risk of LS. Walking speed was assessed by the 10-m walking test. Maximal isometric muscle strengths of the knee extensors were examined, and the weight bearing index (knee extension strength/body weight) was calculated. To assess an independent association between blood parameters and LS, the area under the receiver operating characteristic curve analysis (area under the curve, sensitivity, and specificity) and a binary logistic regression analysis were performed with adjustment for age.ResultsOf the 223 subjects, 119 (53.3%) fulfilled the diagnostic criteria for LS (including a two-step test score < 1.3, difficulty with one-leg standing from 40 cm in the stand-up test, and a 25-question GLFS score ≥ 7). Increased levels of HbA1c were significant risk factors for LS with an OR of 2.62 (OR95%CI = 1.43–4.80), as determined by a logistic regression analysis. Additionally, dehydroepiandrosterone-sulfate (DHEA-S) levels were significant only in the male subjects (OR = 0.992 [OR95%CI = 0.986–0.998]), at a threshold of 88 (AUC; 0.70, sensitivity; 79.6%, specificity; 49.1%). Moreover, 101 of 223 participants (41 men, 60 women) were analyzed for serum albumin levels, with a prevalence of LS at 55.4%, indicating that low levels of albumin were significant risk factors for LS (OR = 0.148 [OR95%CI = 0.023–0.954], p = 0.0445).ConclusionsThese results suggest that higher HbA1c and lower albumin are associated with the prevalence of LS in Japanese middle-aged and elderly individuals. Furthermore, low DHEA-S levels may be useful screening tools for LS in men.

Effects of electrical stimulation on muscle power and biochemical markers during hemodialysis in elderly patients: a pilot randomized clinical trial

BackgroundDecreased physical activity in hemodialysis (HD) patients causes various structural, metabolic, and functional abnormalities due to uremic changes in skeletal muscles. Electrical stimulation (ES) of the lower limbs was found to be effective in patients with cardiac insufficiency for exercise tolerance. This study compared the effects of ES and variable load ergometers on the lower limbs in HD patients.MethodsWe performed a prospective, double-center, open-label, randomized controlled trial. Eligible patients were aged over 65 years, had end-stage renal disease, and underwent maintenance HD. The primary endpoint was muscle power, and the secondary endpoints included changes in dialysis efficiency, serum phosphorus, and inflammatory markers. Thirty HD outpatients were randomly assigned to the following groups: exercise (EX), ES, or control (SED). In EX and ES groups, patients were instructed to exercise twice a week for 12 weeks, depending on their physical capabilities. The safety and efficacy of aerobic training and ES during HD were confirmed when a sudden decrease in blood pressure or any other side effects did not occur. A repeated measures analysis of variance was performed as the principal method to evaluate time (baseline vs. 12 weeks) and group (EX vs. ES vs. SED) comparisons for the experimental outcomes.ResultsThe efficiency of HD significantly increased in the ES and EX groups (p ≤ 0.02). Moreover, the ES group experienced a significant increase in muscle power (p = 0.01) and the weight bearing index (p = 0.04) and a significant decrease in serum phosphorus level (p = 0.04) and tumor necrosis factor-alpha (TNF-α) level (p = 0.04) from baseline to 12 weeks. Furthermore, there was a significant increase in serum TNF-α level (p ≤ 0.03) over time in both the EX and SED groups.ConclusionThe safety and efficacy of aerobic training and ES during HD were confirmed when a sudden decrease in blood pressure or any other side effects did not occur. Therefore, ES may improve the patient’s condition, similar to lower limb exercises, and ES should be considered as an option for rehabilitation programs in HD patients.Trial registrationUMIN Clinical Trials Registry (UMIN-CTR R 000032202); retrospectively registered on April 11, 2018

Qualification of 'Bordô' grape clones in Vale do Rio do Peixe, in the state of Santa Catarina, Brazil

Abstract: The objective of this work was to characterize the productive and qualitative performances of 11 clones of 'Bordô' grape (Vitis labrusca) destined to wine and juice production, in the region of Vale do Rio do Peixe, in the state of Santa Catarina, Brazil. The experiment was carried out in the 2011, 2012, 2014, and 2015 crop seasons. The analyzed yield components were: number of clusters per vine, yield, cluster weight, accumulated yield, and alternate bearing index. The analyzed morphological characteristics of clusters were: number of berries per cluster, berry diameter, cluster compactness index, and cluster length. In order to assess grape quality, the following parameters were analyzed: soluble solids (SS), pH, titratable acidity (TA), SS/TA ratio, total anthocyanins, and total polyphenols. The 'Bordô' grape clones 13 and 16 ('Paco' and 'Bocaina') are the most suitable ones for cultivation in the wine producing region of Vale do Rio do Peixe, as they show the highest yields, production stability, and grapes with adequate quality for wine and juice elaboration.

Thorax Flexibility can be Increased by Standing Pole Exercise

Background: Discussion has been continued about the stability of the spine, and relationship with physical flexibility and exercise function. We have continued physical rehabilitation for various subjects, and proposed clinical application for pole exercise. In this study, we investigated the efficacy of standing pole exercise. Study protocol: The subjects were 9 healthy adults, 26.9 ± 5.9 years old. Method included standing pole exercise and 2 tests before and after the exercise. The exercise has 6 movements, including lateral bending, axis rotation, wave motion, backward spiral, forward spiral and warp and rounding. The pole was 160 cm in length, 610 g in weight. Two tests were percentage vital capacity (%VC) and weight bearing index (WBI), which showed significant differences between before and after the exercise (p<0.01). Discussion and conclusion: Theoretical mode of spinal stability has relationship with inner/outer core stability, flexibility, expandability, curved angles in spinal alignment, and so on. In current study, standing pole exercise would be effective for increased %VC and WBI, which may be from increased flexibility and expandability. These data would be basal data for clinical application and research development in the future.

Pole Exercise Causes Body Changes in Physical Flexibility and Exercise Function

Background: Theoretical mode of spinal stability and core stability has been introduced previously, which has proceeded to rehabilitative approaches. We have focused on physical flexibility and exercise function, and firstly devised an original pole exercise in sitting position that can be done simply and cost-effectively.Subjects and Methods: The subjects 11 healthy young adults, 27.0 ± 5.6 years old. Methods included the intervention of pole exercise with Exercise of the thorax, lower thoracic vertebrae and pelvis, upper thoracic vertebrae and pelvis. Before and after the exercise, we investigated examinations. Tests of physical flexibility were Wing Test, Thomas Test, Shoulder Extension Test, straight leg raise (SLR), Body warp prone position, Heel Buttock Distance (HBD) and Finger Floor Distance (FFD). Tests of exercise functions were Back Muscle Strength (BMS), Weight Bearing Index (WBI), Functional Reach Test (FRT) and closed eye leg standing time.Results: The data of 7 flexibility tests and 4 exercise function tests revealed the significant differences between before and after the pole exercise (p<0.05). These tests would cover detail aspects of several human abilities in physiotherapy.Discussion and Conclusion: In current study, pole exercise seems to be clinically simple and easy method to perform. These results suggested that pole exercise including 6 movements would have clinical efficacy as to physical flexibility and exercise function in short period. Currently obtained data could become fundamental data for clinical application and research development in the future.

High-fat diet exacerbates pain-like behaviors and periarticular bone loss in mice with CFA-induced knee arthritis.

Our aim was to quantify nociceptive spontaneous behaviors, knee edema, proinflammatory cytokines, bone density, and microarchitecture in high-fat diet (HFD)-fed mice with unilateral knee arthritis. ICR male mice were fed either standard diet (SD) or HFD starting at 3 weeks old. At 17 weeks, HFD and SD mice received intra-articular injections either with Complete Freund's Adjuvant (CFA) or saline into the right knee joint every 7 days for 4 weeks. Spontaneous pain-like behaviors and knee edema were assessed for 26 days. At day 26 post-first CFA injection, serum levels of IL-1β, IL-6, and RANKL were measured by ELISA, and microcomputed tomography analysis of knee joints was performed. HFD-fed mice injected with CFA showed greater spontaneous pain-like behaviors of the affected extremity as well as a decrease in the weight-bearing index compared to SD-fed mice injected with CFA. Knee edema was not significantly different between diets. HFD significantly exacerbated arthritis-induced bone loss at the distal femoral metaphysis but had no effect on femoral diaphyseal cortical bone. HFD did not modify serum levels of proinflammatory cytokines. HFD exacerbates pain-like behaviors and significantly increases the magnitude of periarticular trabecular bone loss in a murine model of unilateral arthritis.

Single Leg Up Down テストと体重支持指数（Weight Bearing Index）の関連

〔目的〕我々が考案したSingle Leg Up Downテスト（以下SLUDテスト）と体重支持指数（以下WBI）の関連について検討すること．〔対象と方法〕中学野球選手202名にSLUDテストおよびWBI（等尺性最大膝伸展筋力を体重で除した値）を測定した．非投球側のSLUDテスト遂行可能な高さで群分けし，各群間のWBIをKruskal-Wallis検定，多重比較法を用いて比較した．〔結果〕SLUDテスト40 cm，30 cm，20 cm，10 cmのWBIの平均はそれぞれ0.79±0.18，0.87±0.20，1.00±0.19，1.04±0.24であり，40 cmと30 cmの各群に対して，20 cm，10 cmの各群が高値を示した．〔結語〕スポーツ選手に必要な筋力はWBI 1.0以上とされていることからも，20 cm台からのSLUDテスト遂行の可否が下肢筋力のスクリーニングテストとして有用であることが示された．

Effect of 12-month rehabilitation with low loading program on chronic respiratory disease.

[Purpose] The purpose of this study was to examine the effect of 12-month rehabilitation with low loading program on chronic respiratory disease. [Subjects and Methods] Twelve patients with chronic respiratory disease participated in this study, in which the effect of long-term rehabilitation for 12 months was assessed. Nine patients had chronic obstructive pulmonary disease, two had asthma, and one had interstitial pneumonia. In all patients, symptoms, lower-extremity strength, walking distance, activities of daily living, and quality of life were investigated to examine the effect of respiratory rehabilitation. [Results] After 12 months, the isometric knee extension strength and weight-bearing index both showed a significant increase. [Conclusion] The findings of this study suggested that improvement in lower-limb muscle strength can be achieved through long-term intervention, and indicated the validity of repetitive standing and walking exercises.

施設通所高齢者における下肢筋力の体重支持指数と運動機能の関係

施設通所高齢者における下肢筋力の体重支持指数と運動機能の関係

Quadriceps muscle strength, radiographic knee osteoarthritis and knee pain: the ROAD study.

BackgroundThe objective of this study was to clarify the association of quadriceps muscle strength with knee pain using a large-scale, population-based cohort of the Research on Osteoarthritis/osteoporosis Against Disability (ROAD) study.MethodsFrom the 2566 subjects at the third visit of the ROAD study, the present study analyzed 2152 subjects who completed radiographic examinations and measurements of muscle strength and mass (690 men and 1462 women; mean age, 71.6 ± 12.2 years). Knee pain was assessed by an experienced orthopedist. Knee osteoarthritis (OA) was defined according to Kellgren-Lawrence (KL) grade. Quadriceps muscle strength and muscle mass at the lower limbs were measured by the Quadriceps Training Machine (QTM-05F, Alcare Co., Ltd. Tokyo, Japan) and the Body Composition Analyzer MC-190 (Tanita Corp., Tokyo, Japan), respectively.ResultsQuadriceps muscle strength and weight bearing index (WBI: quadriceps muscle strength by weight) were significantly associated with knee pain after adjustment for age and body mass index, whereas grip strength and muscle mass at the lower limbs were not. The significant association of quadriceps muscle strength with knee pain was independent of radiographic knee OA.ConclusionThe present cross-sectional study showed an independent association of quadriceps muscle strength with knee pain.Electronic supplementary materialThe online version of this article (doi:10.1186/s12891-015-0737-5) contains supplementary material, which is available to authorized users.

Effect of a Two-year Health Program on Brain Function, Physical Fitness and Blood Chemistry

Background: Protocols for carrying out health programs for aged adults have not been clearly presented. Thus, the aim of this study is to examine the effects from the first year to the second year of the Matsumoto health promotion program and to make use of the results in future health promotion for elderly people. Method: The city of Matsumoto offered local residents a two-year health program which includethe use of a pedometer, anthropometry, blood pressure, go/no-go brain function, a physical fitness test and a blood chemistry test. Eighty-six elderly people age 65.9 ± 5.9 years participated in the program. All the participants were given pedometers and a target of 7,000 to 8,000 steps per day was set based on the weight-bearing index. During the first year, the participants did their walking exercise and attended a series of monthly seminars. Then the second year, the participants continued their walking exercise, attended series of monthly seminars and began a 2 hour weight training once a week. Result: The result from the pedometer in the first year showed that the average daily walking step was 6552.9 ± 474.2. The second year, the average daily walking steps was 7170.4 ± 547.9. The results from first year to second year showed significant improvement; the number of incorrect response in the go/no-go tasks (before: 5.3 times ± 0.4, after: 2.9 times ± 0.2, p<0.001), sit-ups(before: 12.4 times ± 0.6 times, after: 17.4 times ± 0.8, p<0.001), sit and reach flexibility(before: 39.4 cm ± 1.2, after: 42.0 cm ± 1.3, p<0.05), eyes open single leg stance(before: 86.2 sec ± 5.4, after: 98.7 sec ± 4.6, p<0.001), 10-meter obstacle walk(before: 5.1 sec ± 0.1, after: 4.0 sec ± 1.1, p<0.001), 6-minute walking(before: 637.4 m ± 5.3, after: 716.6 m ± 9.8, p<0.001), the uric acid(before: 5.4 mg/dL ± 0.2, after: 5.1 mg/dL ± 1.2, p<0.001) and HDL (before: 68.5 mg/dL ± 2.4, after: 73.2 mg/dL ± 2.6, p<0.001) in the blood test. Conclusion: These results from the two-year program suggests that the increase in walking and the 2 hour weight training may reflect the influence of wearing a pedometer, and improved anthropometry, blood pressure, brain function, physical fitness and blood chemistry. However, the girth of the abdomen, handgrip strength and blood chemistry did not show significant improvement. Thus we must think about enlightenment program that wouldinclude muscular strength training and nutrition.

Association between gait speed and bone strength in community-dwelling postmenopausal Japanese women

It is unclear whether gait speed can be used to predict bone status or to diagnose osteopenia or osteoporosis. The aim of our study was to determine whether the measurement of physical performance predicts bone strength in community-dwelling postmenopausal Japanese women. We measured speed of sound (SOS), weight bearing index (WBI), maximum or usual gait speed, step length of each gait, single leg balance time with or without eyes closed, and grip strength among 1,061 postmenopausal women (mean age ± standard deviation 68 ± 8 years). After adjustments for age and body mass index, SOS was associated with maximum or usual gait speed and with step length during maximum speed gait, but not with WBI, grip strength, single-leg balance time with or without eyes closed, or step-length time during usual gait speed. When subjects were divided into quartile groups based on WBI (a marker of lower extremity strength), significant associations between usual or maximum gait speed and SOS were found only in the lowest and second lowest groups (first and second quartiles). Finally, analysis of sensitivity and specificity at various cut-off points of maximum gait speed to predict decreased SOS showed relatively high specificity compared with the corresponding sensitivity among those with low gait speed. Maximum gait speed together with WBI may be a useful and specific test to predict bone status in postmenopausal older women.

Weight-bearing Index Or Grip Strength, Which Is Better Physical Function Predictor For Well-functioning Elderly?

Weight-bearing Index Or Grip Strength, Which Is Better Physical Function Predictor For Well-functioning Elderly?

Changes in the relative contribution of each leg to the control of quiet two-legged stance following unilateral plantar–flexor muscles fatigue

We used unilateral plantar-flexor muscles fatigue to assess the capacity of the central nervous system to adapt quiet two-legged stance control to a unilateral ankle neuromuscular perturbation. Eighteen young healthy adults stood barefoot with their eyes closed and were asked to sway as little as possible. The Experimental group (n = 9) executed this postural task in two conditions, before (pre-test) and following the completion of a fatiguing exercise designed to induce a muscular fatigue in the plantar-flexor muscles of their dominant leg (post-test). For the Control group (n = 9), this fatiguing exercise was replaced with a standing rest period corresponding to the fatiguing exercise. Results of the Experimental group showed no significant difference between the weightbearing index measured in the pre-test condition and that observed in the post-test condition. Results further revealed that unilateral plantar-flexor muscles fatigue yielded different effects on the centre of foot pressure (CoP) displacements under the non-fatigued leg and under the fatigued leg: a wider surface area of the CoP displacements was observed under the non-fatigued than under the fatigued leg, and a higher mean speed of the CoP displacements was observed under the non-fatigued leg only in the post-test relative to the pre-test condition. These findings evidenced that the contribution of each leg to the control of quiet two-legged stance is modified as a result of muscle fatigue of unilateral plantar-flexor muscles. The greater contribution of the non-fatigued leg could be viewed as a fatigue-induced adaptive change in the control of quiet two-legged stance in response to an alteration of the unilateral ankle neuromuscular function induced by unilateral plantar-flexor muscles fatigue.

Relationship between Balance Performance and Leg Muscle Strength in Elite and Non-Elite Junior Speed Skaters

The purpose of the present study was to examine the relationship between balance performance during one-leg and two-leg standing and leg muscular strength in junior speed skaters, and to formulate one indicator for on-land training. There were a total of 48 subjects comprising 22 junior elite and 26 junior non-elite speed skaters. The method involved analyzing the unit trajectory length (LNG/TIME), the peak value for center of gravity fluctuations (RMS) and the area where fluctuations in the center of gravity are concentrated (SD-A) in keeping one-leg and two-leg standing; and measuring the maximum isometric muscular strength for knee extension with a leg muscular strength measurement device, and thereby calculating a weight-bearing index (WBI). As far as the characteristics for the center of gravity were concerned, significantly lower values in the elite group compared with the non-elite group were exhibited for the peak center of gravity fluctuations (RMS) and the area in which fluctuations in the center of gravity were concentrated (SD-A). However, no significant differences were observed in the unit trajectory length (LNG/TIME). In addition, no significant differences between the groups were observed when the right leg was kept standing. The elite group exhibited significantly higher values in the weight-bearing index (WBI) compared with the non-elite group for both legs. With regards to the differences between the left and right leg WBI, the elite group exhibited significantly higher values for the left leg than the right leg, but no significant difference was observed between left and right in the non-elite group. Based on this, it is suggested that there is a need to carry out qualitative training for improving the ability to keep the left leg standing in a posture simulating skating, and to carry out quantitative training for increasing the muscle strength of knee extensors, in order to improve the competitiveness of junior speed skaters.