National athletic trainers' association position statement: fluid replacement for athletes.

OBJECTIVE: To present recommendations to optimize the fluid-replacement practices of athletes. BACKGROUND: Dehydration can compromise athletic performance and increase the risk of exertional heat injury. Athletes do not voluntarily drink sufficient water to prevent dehydration during physical activity. Drinking behavior can be modified by education, increasing accessibility, and optimizing palatability. However, excessive overdrinking should be avoided because it can also compromise physical performance and health. We provide practical recommendations regarding fluid replacement for athletes. RECOMMENDATIONS: Educate athletes regarding the risks of dehydration and overhydration on health and physical performance. Work with individual athletes to develop fluid-replacement practices that optimize hydration status before, during, and after competition.

Comparison of support provided by a semirigid orthosis and adhesive ankle taping before, during, and after exercise.

The purpose of this study was to compare the relative effectiveness of athletic taping and a semirigid orthosis in providing inversion-eversion range restriction before, during, and after a 3 hour volleyball practice. The effect of each support method on the subjects' vertical jumping ability was also assessed. Fourteen ankles were treated with both methods of support. Passive inversion-eversion range of motion was measured on an ankle stability test instrument during five testing sessions: 1) before support, 2) before exercise, 3) 20 minutes during exercise, 4) 60 minutes during exercise, and 5) after exercise. The two-way analysis of variance and posthoc comparisons revealed maximal losses in taping restriction for both inversion and eversion at 20 minutes into exercise. The orthosis demonstrated no mechanical restrictive failure until before and after exercise comparisons were made, and then only eversion range of motion was compromised. Neither support system affected subjects' vertical jumping ability. These results suggest that the semirigid orthosis may be more effective than taping in providing initial ankle protection and in guarding against ligamentous reinjury.

Bilateral inversion-eversion range of motion comparisons among college athletes.

The purpose of this study was to compare bilateral passive inversion-eversion ROM values in the ankles of individuals with no prior history of ankle trauma. Thirty-seven intercollegiate athletes, 25 males and 12 females, participated in this study. Passive inversion-eversion ROM was measured on an ankle stability test instrument, with the ankle positioned at 0 degrees plantarflexion. The ANOVA results demonstrated a significant bilateral difference in inversion ROM at the 0.01 level of confidence and a significant left/right eversion difference at the 0.05 confidence level. These results suggest that many of the assessment procedures utilized by physical therapists in the treatment of ankle ligamentous injuries may be inaccurate, if their validity is dependent upon contralateral comparisons. Factors related to limb dominance and athletic participation may have influenced the findings in this study. J Orthop Sports Phys Ther 1990;11(11):543-546.

The use of physical agents in rehabilitation of athletic injuries.

The competitive athlete's motivation to return to activity following injury presents a challenge to the sports medicine specialist to utilize the most effective rehabilitation procedures available. Safe return to competition necessitates maximal restoration of those components of physical fitness affected by injury (such as muscular strength, power, endurance). Various forms of superficial heat and cold application, deep heat modalities, and electrical currents have been used to supplement therapeutic exercise in this process. In recent years, the therapeutic benefits of cold for the control of exercise-induced edema and as a prelude to performance of prescribed exercise have been widely recognized. Although short wave and microwave diathermy appear to have lost much of their appeal as deep tissue heating modalities, the thermal and mechanical effects of ultrasound continue to make it a widely used modality in sports medicine. Adaptation of alternating electrical currents for use in transcutaneous nerve stimulation has given the sports medicine clinician a useful modality for pain management. The more recently developed "Russian" electrical stimulator provides a promising modality for muscle re-education and restoration of muscular strength.

Gravity perception in decapped roots of Zea mays.

Time-lapse photography and light microscopy were used to determine whether or not sedimentation of the newly developed amyloplasts in the apex of Zea mays L. roots occurred at the time when geotropic responsiveness reappears following removal of the cap. All decapped roots exhibiting a geotropic response had some amyloplast sedimentation in the apical cortical cells. Exposing decapped roots to a centrifugal acceleration of 25 g for 4 h showed that amyloplasts of a similar size and development were not displaced within the cytoplasm when this treatment began 12 h after decapping, whereas displacement did occur when the treatment began 24 h after decapping. This finding indicates the occurrence of a change in the physical characteristics of the cytoplasm between 12 h and 24 h after removing of the cap, which allows amyloplast movement and thus restores gravity perception.

Studies on the movement of indole auxins in willow (Salix viminalis L.).

Auxin activity was detected in honeydew obtained from the aphid Tuberolachnus salignus (Gmelin) feeding on willow (Salix viminalis). Active uptake of (14)C-indolyl-3-acetic acid (IAA) into the sieve tubes was demonstrated by irrigating the cambial surface of willow bark with (14)C-IAA solution and assaying aphid stylet exudate. When, however, (14)C-IAA was applied to the peridermal tissues of the bark or to a mature leaf most of the radioactivity (collected in honeydew or stylet exudate) co-chromatographed with indolyl-3-acetyl-aspartic acid (IAAsp). The presence of IAAsp in honeydew was not affected by extraction procedure or by aphid metabolism. Honeydew obtained from willow treated with (14)C-tryptophan contained only (14)C-tryptophan. When (14)C-IAA was applied in agar to the cut end of willow segments the radioactivity was found to move in a basipetally polar manner. The direction of movement of radioactivity in the sieve tubes, however, was found to be influenced by the proximity of the roots. Nevertheless, there was evidence that endogenous auxin in the sieve tubes does move in a predominantly basipetal direction.