International SportMed Journal - Volume 10, Issue 4, 2009
Volume 10, Issue 4, 2009
Low back pain intensity, microcirculation and muscle performance of the multifidus following back muscle strengthening in young elite oarsmen : original research articleSource: International SportMed Journal 10, pp 163 –175 (2009)More Less
Background: Low back pain is a problem that not only affects the general population but is also an underestimated problem in athletes involved in endurance sports. Rowing in particular has been associated with a high incidence of exercise-associated low back pain.
Research question: The present study hypothesises that a device-assisted training programme leads to an improvement of the microcirculation and muscle performance of the multifidus muscle, which contributes to the reduction of exercise-associated low back pain.
Type of study: Before-and-after trial Methods: Thirteen young elite oarsmen (five males, eight females; age range: 14.6-15.3 years) with exercise-associated low back pain performed a device-assisted training programme for isometric exercise of the low back 2-3 times per week for a duration of three months. To measure the training effect on the microcirculation and muscle performance of the multifidus muscle, simultaneous measurements of intramuscular pressure, tissue oxygen saturation, and median frequency shift in the surface electromyography were performed before and after the training period. The pain course was evaluated using a visual analogue scale.
Results: The device-assisted training programme resulted in a median increase in maximum trunk torque (19N) and isometric exercise duration (44sec) coupled with a decrease in the frequency, duration and intensity of pain in 12 of 13 oarsmen. During the isometric endurance test, the increase in intramuscular pressure (17.0mmHg vs. 8.9mmHg) and the drop in tissue oxygen saturation (-6.6mmHg vs. 0.1mmHg) were significantly greater before training than after training. The median frequency shift in the surface electromyography remained unchanged.
Conclusions: As the device-assisted training programme led to a reduction of exercise-associated low back pain and in addition resulted in an improvement of the microcirculation and muscle performance of the multifidus muscle, the hypothesis of this study seems to be confirmed. Therefore the findings of the present study strongly indicate that muscle training focusing on the multifidus muscle should be taken into consideration in the planning of back training programmes for oarsmen.
Source: International SportMed Journal 10, pp 176 –185 (2009)More Less
Background: Head trauma may result in many kinds of otoneurologic disorders. However, there are very few studies associated with the evaluation of the disorder. Research question: The aim of the study is to clarify the effects of long-term impact to the head in advanced boxers regarding vestibular evoked myogenic potentials (VEMP). Type of study: Prospective study. Material and methods: VEMPs were collected from 14 advanced boxers (13 M, 1 F, aged 16-28 years). The otoscopic findings, audiograms and caloric test were recorded. The VEMP responses of strong side (right for right-handed) and weak side were compared to each other and to the healthy volunteers. Results: The 14 enrolled subjects had been engaged in the sport of boxing for 4 to 15 years (median: 8.9 years). In comparison with the control group, the results of the caloric test of the subjects were not significantly different (p>0.05). The VEMP responses in boxers showed significant delay of p13 and n23 latencies in both strong side and weak sides in comparison with healthy volunteers (p<0.05). Moreover, the p13 and n23 latencies of VEMP responses showed significant delay over strong side as compared with the weak side (p<0.05). Conclusion: VEMP responses were significantly affected by chronic head trauma in the boxers. Furthermore, p13 and n23 latencies of VEMP responses of strong side showed significant delay compared with those of the weak side.
Lower extremity stiffness modulation : effect of impact load of a landing task from different drop heights : original research articleAuthor Li-I. WangSource: International SportMed Journal 10, pp 186 –193 (2009)More Less
Background: The characteristics of stiffness resulting from increased impact loads dropped from various heights are still uncertain. Aim: This study aimed to examine lower extremity stiffness regulation at various impact loads, and the relationship between lower extremity stiffness and the impact load. Methods: Twenty male subjects were recruited from a university's physical education department. Each subject performed a landing task from drop heights of 40, 60, and 80cm (DL40, DL60, and DL80) respectively. Leg stiffness, joint stiffness, peak vertical ground reaction force, time to peak vertical ground reaction force, loading rate, and peak proximal tibia anterior shear force were measured. Correlations of leg stiffness and joint stiffness with peak vertical ground reaction force, time to peak vertical ground reaction force, loading rate, and peak proximal tibia anterior shear force during the drop landing task were assessed. Results: The study found that increased impact load from DL40 to DL60 reduced leg stiffness, but the peak vertical ground reaction force, time to peak vertical ground reaction force, and loading rate were unchanged. When the impact load increased from DL60 to DL80, leg stiffness no longer decreased, and the knee joint stiffness increased significantly. Meanwhile, the peak vertical ground reaction force and loading rate increased significantly, and the vertical ground reaction force peaked earlier than with DL40 and DL60. Further, knee joint stiffness was significantly correlated with the peak proximal tibia anterior shear force. Conclusions: Reduced leg stiffness with increasing impact load may decrease the risk of future lower extremity injury. A significant increase in knee joint stiffness at DL80 increases the risk of knee joint injury, especially injury of the ACL.
Effects of supplement consumption on homocysteine levels of competitive swimmers : original research articleSource: International SportMed Journal 10, pp 194 –204 (2009)More Less
High homocysteine (Hcy) concentrations are associated with the risk of cardiovascular disease. Despite the known high incidence of the use of food supplements by athletes, little is known about the possible effect of the use of protein supplements containing methionine (Met) on Hcy metabolism. The objective of the present study was to test the hypothesis that the consumption of protein supplements can increase the ingestion of Met and Hcy levels. Seventeen swimmers (8 males and 9 females) aged 20.11±2.26 years were evaluated in terms of biochemical profile and habitual food consumption. After the application of a questionnaire about the use of food supplements, the swimmers were divided into three groups: control (C), energy supplement consumption (ES), and protein-energy supplement consumption (PES). The results showed that 82% of the individuals used some type of supplement, with PES being consumed by 36% of them. The addition of a supplement did not significantly increase protein or methionine intake in the PES group compared to C and ES groups. No significant differences in plasma Hcy concentrations were detected between groups, but a positive correlation was observed between Met intake and serum Hcy (r = 0.65; p=0.01), and a negative correlation was also detected between serum Hcy and serum vitamin B12 (r = -0.52; p=0.03). In conclusion, it was observed that, even in the absence of protein intake modulation and changes in Hcy levels, the ingestion of methionine through food supplements is associated with plasma Hcy levels.
Association of physical performance and health-related factors among elderly Korean subjects : original research articleSource: International SportMed Journal 10, pp 205 –215 (2009)More Less
Background: Although there is substantial evidence indicating the importance of physical performance in older adults, not many studies have examined the association between physical performance and health-related factors for the elderly Korean population. Research question: To investigate the relationship between physical performance and health-related factors among elderly Korean people. Type of study: Cross-sectional study. Methods: A total of 360 Korean older adults (men=154 and women=206) age: 72.1± 5.7 years, were recruited from six different Old Adult Health Centres in Seoul, Korea. Six tests including chair standing (CST), get up and go (3 metres), standing reach (SRT), 6-minute walking, hand-grip, and the 1.6km walking test were performed. Serum levels of fasting glucose, insulin, triglyceride (TG), total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), and high sensitivity C-reactive protein (hs-CRP) were measured. Body composition was also measured. Results: The get up and go test was correlated with TG, lean mass, SBP and hip C (r = .15, r = -.264, r = .136, and r = .148). SRT was correlated with TG (r = -.15) and lean mass (r = .336). Significant correlations were also found for lean mass and WHR with hand-grip strength (r = .818 and r = .255). The 6-minute walking test was correlated with lean mass, fat mass, waist, and hip C (r = .421, r = -.159, r = -.144 and r = -.23). CST had a significant correlation with HDL-C, lean mass, fat mass, BMI, waist and WHR (r = .187, r = .183, r = -.18, r = -.134, r = -.157, and r = -.159). The 1-mile walking test was correlated with TG, insulin, HOMA-IR, lean mass, and fat mass (r = .176, r = .261, r = .254, r = -.23 and r = .213). VO2max was correlated with lean mass, TC, TG, TC/HDL, insulin, HOMA-IR, fat mass, BMI, resting HR, and hip C (r =.353, -.194, r = -.245, r = -.197, r = -.258, r = -.21, r = -.346, r = -.237, r = -.257 and r = -.191).
Conclusions: Lean body mass was well correlated with all physical performance tests, and cardiorespiratory endurance was associated with body composition and metabolic parameters in older Korean adults.