Cold water swimming seems to have a positive effect on insulin metabolism, although here too, the effect appears to be sex-specific [3,56]. In a field study, 30 cold water swimmers were examined for six months with regard to body composition and insulin sensitivity [3]. The chilled water swimmers were overweight compared to a control group and had a higher percentage of body fat with differences between the sexes. For female and swimmers with lower body fat percentage, there was an increased insulin sensitivity as well as a reduction in insulin secretion and resistance [3].
However, it can be assumed that the drop in core body temperature in ice swimmers is less rapid than in pool swimmers with more subcutaneous fat [40,43]. Overweight people who are acclimatized to the cold water and have the appropriate experience are more likely to tolerate a longer stay in the cold water than people with little body fat tissue and those who are not acclimatized [40,79,102,103]. An experienced, overweight ice swimmer with a BMI > 35 kg/m2 and 45% body fat never became hypothermic, even after several stays in ice-cold water [40]. Keatinge et al. [104] described a case of an Icelandic fisherman who survived in the ice-cold water, in part due more adipose tissue. After his boat sank and his two colleagues drowned within 10 min, he swam back to the shore in the 5 C cold sea, taking him approximately 6 hours to complete [104].
the tired swimmer case study answer key.zip
If you are a good swimmer and have had lessons, keep an eye on friends who aren't as comfortable or as skilled as you are. If it seems like they're getting tired or a little uneasy, suggest taking a break from swimming for a while.
This case study presents an 18-year-old male recently diagnosed with CMT disease type 1. CMT disease is the most common genetically inherited neuromuscular disorder affecting approximately 1 in every 2500 people [1]. There are two major subtypes of the disease, with type 1 characterized by slow nerve conduction as a result of demyelination, and type 2 associated with axonal degeneration [2]. Both subtypes primarily affect motor neurons with sensory nerves affected to a lesser extent [2]. The onset of CMT disease typically occurs in the first 20 years of life and often has a slow progression [3]. Although the progression of the disease varies, symptoms commonly first arise in the distal lower extremities, with muscle weakness, sensory loss, and reduced reflexes [3]. As CMT disease progresses, the proximal lower extremities, as well as upper extremities can also become affected [2].
The purpose of this case study is to provide an example of how an individual may present with CMT disease in the early stages. This information may assist physiotherapists or other healthcare providers in recognizing the symptoms of CMT disease and knowing when to refer their patient to a neurologist to make a diagnosis. As previously mentioned, the onset and progression of the disease can vary. Therefore, this case represents how a more conventional patient may present. It is possible for the disease to have a much earlier onset and present with a more rapid progression, as seen in a case study on a Paralympic swimmer with CMT disease [4]. Moreover, this case provides examples of outcome measures that can be used to measure the progression of CMT disease over time. Due to the degenerative nature of the condition, symptoms cannot be improved. However, various interventions are outlined in this case study that can be utilized to assist in slowing the progression of the disease.
Rip currents are near-shore, narrow, seaward directed flows of fast-moving water that pose a serious threat to swimmers. The instinctive reaction of a misinformed swimmer caught in a rip might be to fight the rapid current directly, which can lead to fatigue, panic and, in some cases, drowning (NOAA 2019). To put this danger into perspective, in Australia 89% of the 25,000 surf rescues conducted by lifeguards per year are carried out due to rip current accidents, with an average of 21 rip-related deaths per year (Short and Hogan 1994; Brighton et al. 2013). In the USA, the number of rip-related fatalities can exceed 100 in a given year (Brewster et al. 2019).
The aim of this theoretical study is not to estimate the actual energy/power (in Joules/Watts) expended by a swimmer when escaping a rip current. Such a task would need to account for the significant complexity associated with the actual hydrodynamics of rips, the mechanics of human swimming (considering different swimming techniques and abilities) and the metabolism of swimmers. Instead, this paper aims to generate some simple physics-based criteria to judge a given strategy relative to another, and model simplicity is prioritised for the sake of generality in the results, as previously discussed. Just as the rip current structure has been simplified in Sect. 2.1, here we idealise a swimmer as a rigid object of arbitrary geometry subject exclusively to its self-generated propulsive force, \(\varvecF_s\), and the opposing, flow-induced drag force, \(\varvecF_D\). A consequence of this simplification is that we will approximate the real work done by the swimmer as the work done (by our rigid object) against the drag force. The former (the real work) is of course frame-invariant, while the latter (our approximation) is not, as we elaborate below.
The trapped swimmer attempts to swim directly back to the shore against the current (see Fig. 2a). This strategy is universally discouraged by lifeguards due to the risk of exhaustion and subsequent drowning. This strategy is investigated as a baseline against which to compare other strategies. In all strategies, the swimmer is assumed to be trapped at the centreline of the rip current and escapes at the time-independent speed \(V_e \equiv \left\Vert \varvecv_s \right\Vert\) (measured from \(K_0\)), so in this case \(\varvecv_s = (0,-V_e)\), as shown in Fig. 2a. The flow velocity, however, is not the same in the rip neck and in the central zone where the feeder channels meet, with values of \(\varvecv_s = (0,V_r)\) for the former and \(\varvecv_s = (0,V_f)\) for the latter. Therefore, we estimate the work done by the swimmer using Strategy 1 (S1) in these two zones separately, as follows (using eq. 4):
Results are summarised in Tables 3 and 4. The main conclusions arrived to in Sect. 3.1 are confirmed. The worst strategy tends to be S1 (though here S3 is sometimes worse), with the best strategy being S4, followed by S2, in agreement with previous research (Miloshis and Stephenson 2011; Brander et al. 2011; RNLI: Rip currents 2020). These remarks are irrespective of starting distance, energetic metric (i.e. work or power) or whether a realistic or idealised rip is employed. Although the particular values of the ratios \(W_1/W_2,3,4\) and \(P_1/P_2,3,4\) will naturally depend on the specific rip and swimmer (see also Sect. 4), a conservative reading of these results suggests that swimming directly against the current (S1) can demand several times more energy and power than strategies encouraged by experts. It is also worth noting that predictions of the work and power ratios based on the idealised rip model proposed here are generally in good agreement with those obtained from the realistic rip current field. This may be taken as a successful, albeit very coarse, validation of the model presented in this study. Note that a proper validation would require sophisticated experiments or simulations that are currently non-existent, and which are well beyond the scope of this paper.
Weis, R. (2017). Introduction to Abnormal Child and Adolescent Psychology, Third Edition. Thousand Oaks, CA: Sage.The case study is based on interviews conducted by Paul Grondahl for the Albany Times Union.
Inflated responsibility for misfortune: Youths with OCD often believe that if something bad happens to a loved one, they are somehow responsible for this negative event. Although there is no evidence of this distortion in the case study, a clinician might want to assess further to see if Isabella exhibits this cognitive distortion.
Yes, approximately 25% to 50% of children with tic disorders also have OCD. Clinicians should routinely assess the presence of OCD and ADHD (another frequently co-occurring disorder) in children like David. The case study suggests that David probably does not have obsessions or ADHD-related behaviors, however.
The model posits that unrealistic standards for thinness and beauty perpetuated by the media also contribute to the development of eating disorders. Although media influences are not described in the case study, it is reasonable that Miranda is a consumer of these influences, which could affect her desire for thinness and her eating behavior.
Competitive swimming is a single-bout event (e.g., 100-m swimming, 200-m swimming). Therefore, studies that examined the effects of sodium bicarbonate on single-bout swimming tasks likely offer the most practically important findings for competition [59, 64, 67, 92, 121, 142]. Lindh et al. [67] conducted a study that involved nine elite male swimmers who performed 200-m freestyle swimming after the ingestion of placebo or 0.3 g/kg of sodium bicarbonate. In this study, swimming time following placebo ingestion was 114 3.6 s. Ingestion of sodium bicarbonate reduced the time needed to complete 200-m of swimming on average by 1.8 s (1.6%). Despite this finding, other studies investigating the effects of sodium bicarbonate on 200-m swimming performance and did not report significant ergogenic effects of sodium bicarbonate among highly trained swimmers [59, 142]. Reasons for this discrepancy in the findings are currently unclear, but they may be associated with the individual variation in responses to sodium bicarbonate supplementation and/or due to the small samples (n = 6 to 7) included in these studies [59, 142].
Several studies have also explored the effects of sodium bicarbonate on interval swimming performance, which is relevant for the interval-based training practices of swimmers [42, 102, 124, 186]. In the first study on this topic, Gao et al. [42] examined the effects of sodium bicarbonate on swimming velocity using a 5 100-yard swimming protocol, with a 2-min rest between intervals. Results showed that sodium bicarbonate increased swimming velocity in swimming intervals 4 and 5 (2%). A similar ergogenic effect (1.1% to 2%) was also reported in studies using 8 25-m (5-s rest) and 4 50-m swimming (1-min rest) protocols [102, 124]. 2ff7e9595c
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