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The Importance of Salt in the Athlete’s Diet.

Valentine V

Curr Sports Med Rep. 2007 Jul ; 6(4): 237-40

Salt consists of sodium and chloride, and is important for normal physiologic function. High sweat rates in athletes result in loss of both fluids and sodium. Fluid replacement with hypotonic solutions will lead to incomplete rehydration and possible complications such as hyponatremia, decreased performance, heat cramps, or other heat-related illness. There is significant individual variation in sodium loss during activity. In some the losses can be replaced by normal dietary intake, whereas in others the losses can be dramatic and increased dietary intake is essential. There are various methods to increase sodium intake, such as increased use of table salt on foods, salty snacks, adding salt to sports drinks, and use of salt tablets. Emphasis on replacement of fluids is also important, but care must be taken to avoid overhydration. Simple measures such as recording daily pre- and postexercise body weight can aid in making fluid and sodium ingestion decisions; in some cases, a comprehensive evaluation is necessary.

From HubMed Abstracts

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Exercise training restores aerobic capacity and energy transfer systems in heart failure treated with losartan.

Kemi OJ, Høydal MA, Haram PM, Garnier A, Fortin D, Ventura-Clapier R, Ellingsen O

Cardiovasc Res. 2007 Jun 19;

OBJECTIVE: Clinical and experimental studies demonstrate that exercise training improves aerobic capacity and cardiac function in heart failure, even in patients on optimal treatment with angiotensin inhibitors and beta-blockers, but the cellular mechanisms are incompletely understood. Since myocardial dysfunction is frequently associated with impaired energy status, the aim of this study was to assess the effects of exercise training and losartan on myocardial systems for energy production and transfer in heart failure.

METHODS: Maximal oxygen uptake, cardiac function and energy metabolism were assessed in heart failure after a myocardial infarction induced by coronary artery ligation in female Sprague-Dawley rats. Losartan was initiated one week after infarction and exercise training after four weeks, either as single interventions or combined. Animals were sacrificed 12 weeks after surgery.

RESULTS: Heart failure, confirmed by left ventricular diastolic pressure >15 mmHg and by >20 mmHg drop in peak systolic pressure, was associated with 40% lower aerobic capacity and significant reductions in enzymes involved in energy metabolism. Combined treatment yielded best improvement of aerobic capacity and ventricular pressure characteristics. Exercise training completely restored aerobic capacity and partly or fully restored creatine and adenylate kinases, whereas losartan alone further reduced these enzymes. In contrast, losartan reduced left ventricle diastolic pressure, whereas exercise training had a neutral effect.

CONCLUSION: Exercise training markedly improves aerobic capacity and cardiac function after myocardial infarction, either alone or in combination with angiotensin inhibition. The two interventions appear to act by complementary mechanisms; whereas exercise training restores cardiac energy metabolism, mainly at the level of energy transfer, losartan unloads the heart by lowering filling pressure and afterload.

From HubMed Abstracts

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Methods to quantify intermittent exercises.

Desgorces FD, Sénégas X, Garcia J, Decker L, Noirez P

Appl Physiol Nutr Metab. 2007 Aug ; 32(4): 762-9

The purpose of this study was to quantify intermittent training sessions using different types of exercise. Strength, sprint, and endurance sessions were performed until exhaustion. These sessions were quantified by the product of duration and heart rate (HR) (i.e., training impulse (TRIMP) and HR-zone methods), by the product of duration and rate of perceived exertion (RPE-based method), and a new method (work endurance recovery (WER)).

The WER method aims to determine the level of exercise-induced physiological stress using the ratio of cumulated work - endurance limit, which is associated with the naparian logarithm of the ratio of work-recovery. Each session’s effects were assessed using blood lactate, delayed onset muscle soreness (DOMS), RPE, and HR. Because sessions were performed until exhaustion, it was assumed that each session would have a similar training load (TL) and there would be low interindividual variability. Each method was used to compare each of the TL quantifications.

The endurance session induced the higher HR response (p < 0.001), the sprint session the higher blood lactate increase (p < 0.001), and the strength session the higher DOMS when compared with sprint (p = 0.007). TLs were similar after WER calculations, whereas the HR- and RPE-based methods showed differences between endurance and sprint (p < 0.001), and between endurance and strength TL (p < 0.001 and p < 0.01, respectively). The TLs from WER were correlated to those of the HR-based methods of endurance exercise, for which HR was known to accurately reflect the exercise-induced physiological stress (r = 0.63 and r = 0.64, p < 0.05). In addition, the TL from WER presented low interindividual variability, yet a marked variability was observed in the TLs of HR- and RPE-based methods.

As opposed to the latter two methods, WER can quantify varied intermittent exercises and makes it possible to compare the athletes’ TL. Furthermore, WER can also assist in comparing athlete responses to training programs.

From HubMed Abstracts

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Hip extension strength following hamstring tendon harvest for ACL reconstruction.

Geoghegan JM, Geutjens GG, Downing ND, Colclough K, King RJ

Knee. 2007 Jul 10;

Hamstring autograft harvest for ACL reconstruction may have an effect on hip extension strength and this may be important especially in sports that involve high speed running such as soccer, rugby, American football and the sprint disciplines of track and field. This aspect of hamstring tendon harvesting has not been looked at before. We have performed a non-randomised prospective case control study comparing isokinetic hip extension strength following four strand semitendinosus and gracilis tendons (4SHS) and bone-patellar tendon-bone (BPTB) autografts in ACL reconstruction. Isokinetic hip extension was assessed at 3 and 12 months post-operatively using a Kin-Com machine at a speed of 30 degrees per second. Three months post-operatively there was a significant decrease (p<0.05) in the peak force of concentric hip extension in the 4SHS group. There was no evidence that hip extension is weaker following ACL reconstruction with 4SHS tendon autograft than ACL reconstruction with BPTB autograft at 12 months post-operatively. We find no contra-indication to the use of 4SHS tendon autografts in ACL reconstruction in patients who wish to preserve hip extension strength for their sporting activities.

From HubMed Abstracts

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Walking and running plantar pressure analysis before and after resection of tarsal coalition.

Hetsroni I, Ayalon M, Mann G, Meyer G, Nyska M

Foot Ankle Int. 2007 May ; 28(5): 575-80

BACKGROUND: Conservative treatment failure in symptomatic tarsal coalition usually mandates bar resection as a preferred operative alternative. The outcome of this procedure generally has been assessed by clinical measures. The purpose of our study was to evaluate whether plantar pressure distribution is normalized after bar resection.

METHODS: This study compared three groups: nine candidates for resection of tarsal coalition, nine patients between 2 and 4 years after bar resection (not the same patients who were candidates for resection), and nine control subjects. The ankle and hindfoot were evaluated according to the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale. Mean plantar pressure and mean normalized impulses were calculated during walking and running.

RESULTS: Significantly higher AOFAS scores were demonstrated in the postoperative group compared with the preoperative group (p<0.01). Medial midfoot pressures demonstrated the most consistent differences between groups. Preoperative feet had significantly higher medial midfoot pressures compared with the control group both during walking and running. Feet that had resection did not demonstrate significantly higher medial midfoot pressures during walking compared with the control group. However, during running, this segment’s pressures were significantly higher both in preoperative (p=0.000) and in postoperative (p=0.023) feet compared with the control group. Heel segments revealed decreased pressures laterally both in preoperative feet and in postoperative feet compared with the control group.

CONCLUSIONS: Running demonstrates that normal plantar pressures are not recreated after resection of tarsal coalition. However, close to normal walking pressure distribution is consistent with the favorable clinical outcome observed in most patients after bar resection.

CLINICAL RELEVANCE: Regaining full recreational activity after resection of a tarsal coalition, i.e. running, may have implications on abnormal foot loading and torque, thus promoting degenerative changes in the subtalar and adjacent joints.

Via HubMed Abstracts

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