Effects of a novel bicycle saddle on symptoms and comfort in cyclists

Background. While the bicycle frame and other parts of the bicycle have undergone many improvements, the bicycle saddle has remained relatively unchanged since it was first designed more than 100 years ago. Given the number and range of cycling injuries believed to result from the saddle, this is surprising. This study investigated the effects of a novel bicycle saddle on saddle-related comfort and symptoms during cycling.Method. Eleven competitive or recreational cyclists, 6 females and 5 males, performed three 2-hour stationary cycle rides in the laboratory, using their personal bicycles. Ride 1 was performed using the standard bicycle saddle and rides 2 and 3 using the novel bicycle saddle. Subjects reported saddle comfort rating scores (SC) while using the different saddles. Subjects also completed a questionnaire evaluating saddle symptoms (SS) when using either the conventional or the novel bicycle saddle during daily cycling.Results. The most common saddle-related medical complaint with chronic use of the conventional saddle was painful pubic bones, with or without chafing. Others were severe chafing, saddle sores, chafing and back pain, and painful pubic bones associated with a loss of feeling in the pelvic area. The mean SS rating score during the 2-hour laboratory ride was significantly less for the novel saddle (11.6 ± 1.2 versus 19.1 ± 3.2 arbitrary units, P < 0.01). Similarly the mean SC score was significantly lower for the novel saddle (36.2 ± 10.5 v. 54.7 ± 11.2 arbitrary units). Values for both SC scores were similar for rides 2 and 3. On completion of the trial all subjects indicated that they would continue to use the novel saddle in preference to the conventional saddle. Three months later 9 subjects (82%) reported continued use of this saddle in preference to the conventional saddle.Conclusion. These results show conclusively that this novel bicycle saddle: (i) significantly reduced reported symptoms during daily cycling compared with the conventionally designed cycling saddle; (ii) significantly improved saddle comfort during 2-.hour cycles in the laboratory, such that (iii) when given the option the majority (82%) of the subjects chose to use this saddle 3 months later. Furthermore, the beneficial effects of the novel saddle were apparent during its first use, suggesting that the novel saddle is effective because the design is anatomically correct

Acute renal failure in four Comrades Marathon runners ingesting the same electrolyte supplement: Coincidence or causation?

Objectives. To evaluate common factors associated with the development of acute renal failure (ARF) in Comrades Marathon runners.Methods. This was a retrospective case series of 4 runners hospitalised post-race with ARF in the 89 km 2010 Comrades Marathon. The outcome measures were incidence of analgesic use, levels of creatine  phosphokinase (CPK) and degree of electrolyte supplementation (sodium, potassium, calcium and magnesium).Results. The prevalence of ARF was 1/4 125 runners. They presented with rhabdomyolysis (mean admission CPK of 36 294 IU) and hyponatraemia (mean admission blood sodium level of 133 mEq/l). All had ingested an analgesic during the run (3 ingested a non-steroidal anti-inflammatory  drug) and the same readily available anti-cramp electrolyte supplement.  The average amount of supplemental sodium (452 mg), potassium (393 mg), calcium (330 mg) and magnesium (154 mg) ingested via this  particular electrolyte supplement before and during the run did not exceedthe recommended upper limits of daily intake. Three of the runners were Comrades Marathon novices.Conclusions. There is a continuing need to clarify the specific cluster variants that cause ARF in Comrades Marathon runners, as the risk factors appear to have evolved since the first case was described over 40 years ago.S Afr Med J 2011;101:876-878

A lumbar body support (KBS 2000) alters lumbar muscle recruitment patterns in patients with acute-upon-chronic lower back pain

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Factors predicting walking intolerance in patients with peripheral arterial disease and intermittent claudication

Objective. To determine which physiological variables conduce to walking intolerance in patients with peripheral arterial disease (PAD). Design. The physiological response to a graded treadmill exercise test (GTT) in patients with PAD was characterised. Setting. Patients were recruited from the Department of Vascular Surgery, Groote Schuur Hospital, Cape Town. Subjects. Thirty-one patients diagnosed with PAD were included in the study. Outcome measures. During a GTT, peak oxygen consumption (VO2peak), peak minute ventilation (VEpeak), peak heart rate and peak venous lactate concentrations were measured and compared with those from a comparison group. Anklebrachial index (ABI) was measured at rest and after exercise. During the GTT, maximum walking distance (MWD) and pain-free walking distance (PFWD) were measured to determine walking tolerance. Results. Peak venous lactate concentrations did not correlate significantly with either PFWD (r=–0.08; p=0.3) or MWD (r=–0.03; p=0.4). Resting ABI did not correlate with either MWD (r=0.09; p=0.64) or PFWD (r=–0.19; p=0.29). Subjects terminated exercise at significantly (p<0.05) lower levels of cardiorespiratory effort and venous lactate concentrations than did a sedentary but otherwise healthy comparison group: peak heart rate 156±11 v. 114±22 beats per minute (BPM); p=0.001; and peak venous lactate concentration 9.7±2.7 mmol/l v. 3.28±1.39 mmol/l; p=0.001. Conclusion. Perceived discomfort in these patients is not caused by elevated blood lactate concentrations, a low ABI or limiting cardiorespiratory effort but by other factors not measured in this study

Probing the interfacial and sub-surface structure of Si/Si1 – xGex multilayers

The ability to determine structural and compositional information from the sub-surface region of a semiconductor material has been demonstrated using a new time-of-flight medium energy ion scattering spectroscopy (ToF-MEISS) system. A series of silicon–silicon/germanium (Si/Si1 – xGex) heterostructure and multilayer samples, grown using both solid source molecular beam epitaxy (MBE) and gas source chemical vapor deposition (CVD) on Si(100) substrates, have been investigated. These data indicate that each individual layer of Si1 – xGex (x ~ 0.22) in both two- and three-period samples, can be uniquely identified with a resolution of approximately 3 nm. A comparison of MBE and CVD grown samples has also been made using layers with similar structures and composition. The total Ge content of each sample was confirmed using conventional Rutherford backscattering spectrometry

Why We Need a Ruminant Revolution: Combating Malnutrition and Metabolic Illnesses to Enable Sustainable Development

Animal source foods (ASF) are essential for proper human development and function. Livestock in general, and ruminants in particular, are essential components of our sustainable global food systems. Of significant worldwide impact, diets with higher-than-recommended levels of ASF can correct the symptoms of metabolic illnesses, offering hope in arresting the current worldwide epidemic of diabetes and other metabolic diseases. Most dietary policy and recommendations are based on the ill-founded belief that plant-based, high-carbohydrate diets are “healthy.” High-quality scientific evidence does not support the belief that vegetarian diets are healthier than omnivorous or animal-based diets. A Therapeutic Carbohydrate Reduction (TCR) lifestyle approach has demonstrated its efficacy in reversing Insulin Resistance (IR) and the non-communicable diseases associated with, or caused, by it. True sustainability is a multifaceted topic consisting of societal, economic, and ecological aspects. The enormous suffering and financial costs of chronic illness must be acknowledged. The production of high-quality animal protein and animal fat by ruminants from feed resources humans cannot directly utilize will be fundamental to feeding a growing population. This essential food production can preserve and enhance the diverse environments where it takes place. We need a revolution in our thinking of what constitutes a healthy diet, of what causes chronic illness, of the vital role that animal product play in the human diet, and the essential nature of ruminant animal agriculture in meeting humanity’s needs. This will mean overthrowing established policies and institutions, and confronting vested belief systems. We’ll need an effort, analogous to the Green Revolution, to develop and deploy the knowledge and technology necessary to meet the needs of the mid-21st Century world

Avoid adding insult to injury – correct management of sick female endurance athletes

Objectives. To evaluate the efficacy of Ringer&#8217;s lactate, isotonic saline and hypertonic saline on the clinical and biochemical recovery of athletes with exercise-associated hyponatraemic encephalopathy caused by fluid overload.Methods. We retrospectively reviewed serial blood sodium concentrations (Na+) and qualitative signs of recovery and time to recovery in two healthy menstruant females hospitalised with dilutional exercise-associated hyponatraemic encephalopathy after withdrawal from the 2011 Comrades Marathon (89 km) and Argus Cycle Tour (109 km).Results. Improvements in blood Na+ did not occur with intravenous administration of Ringer&#8217;s lactate solution, but did occur with administration of isotonic and hypertonic saline. Qualitative improvements in mental status were not quantitatively related to the biochemical value of blood Na+ or subsequent return to normonatraemia.Conclusions. Hyponatraemia should be suspected in all female athletes presenting to the medical area of endurance races with vomiting, altered mental status and a history of high fluid intake. If a diagnosis of exercise-associated hyponatraemia with cerebral encephalopathy is confirmed, the treatment of choice is administration of an intravenous bolus of hypertonic saline. Administration of Ringer&#8217;s lactate should be discouraged, as this does not correct Na+ and appears to delay recovery