Tech Swim is a segment brought to you by our Swim & Play Coach Antonio Mendonca. He will feature various tips and techniques for improving your swimming
June 13th, 2017 - Shallow Water Blackout (SWB)
There are approximately 140,000 deaths annually to drowning worldwide. Although there are no hard statistics for SWB, it is estimated by a number of sources that SWB is responsible for up to 20% of all drownings. As well it is thought that nearly all drownings or near drownings by advanced or elite swimmers is the result of SWB. Described for several years by the Navy and Divers, SWB is now coming to the forefront for prevention by a number of groups including Swimming Federations, American Red Cross as well as a number of European and Worldwide Swimming Associations.
What is it? SWB is a term describing loss of consciousness arising from oxygen deprivation brought about by voluntary or involuntary hyperventilation. In swimming voluntary hyperventilation occurs when a swimmer intentionally over-breathes or hyperventilates. Involuntary hyperventilation can occur as a result of stress and physical exertion during a workout that pushes the swimmer beyond his/her maximum aerobic capacity (VO2 max). This results in blowing off carbon dioxide (CO2) and essentially lowering serum or blood CO2. What happens next is a cascade of physiological events that can end up in a devastating result for a swimmer.
Lowering serum CO2 causes the following physiological responses:
· Constriction or narrowing of blood vessels in the brain
· Reduced respiratory drive and impaired involuntary reflex for breathing
When a swimmer has exercise-induced hypoxia and is asked to breath hold under the combination of reduced oxygen to the brain and impaired involuntary breathing reflex, loss of consciousness in water can occur with devastating results.
In most near drownings it is estimated that the critical time for a successful rescue or resuscitation occurs within 6 to 8 minutes from the beginning of the event. With SWB the critical time period for a successful resuscitation appears to be much shorter. A number of case reports of witnessed SWB indicate that a successful resuscitation needs to begin within 2 minute of the event occurring. The reason for this is not completely understood, however it can be speculated that brain hypoxia has occurred for many minutes before the blackout. Once the blackout has occurred irreversible brain damage proceeds more rapidly.
The Use of Hypoxic Training in Competitive Aquatic Sports.
Coaches in aquatic sports have used hypoxic training techniques for years. Commonly known as “lung busters”, “over / under”, “under water kick drills” and “Tennessee Turns” many drills have used hypoxic training to try to improve a swimmers breath holding ability and perhaps the anaerobic threshold. These drills have only shown to have dogmatic evidence to support this belief. There are no well-controlled exercise physiological studies to support the use of these drills to improve a swimmers performance. Furthermore they may actually be putting the swimmers at high risk for harm or even death.
It appears that underwater drills preceded by hyperventilation or exhaustion place the swimmer at a higher risk of SWB than do surface hypoxic drills. Most case reports of SWB occur with the swimmer being completely submerged. Extending the breathing pattern on the surface of the water, although not without risk, appears to be a safer form of hypoxic training. The reason for this is that the swimmer is able to take a breath at his or her discretion. In this circumstance aquatic staff, coaches or team members can more quickly recognize any loss of consciousness on the surface.
Hypoxic Training – On the Surface : Recommendations Caution that any drills that require breathing on a restricted schedule should occur on the surface of the water and only in a training program of experienced swimmers in good physical condition with proper supervision and instruction.
With observant lifeguards and coaches, it is unlikely that death would result should a swimmer lose consciousness while swimming on the surface of the water. However, aspiration of water could result in hospitalization.
Common risk reduction strategies include:
· Lifeguards required.
· Prohibit voluntary hyperventilation.
· Structure practice so as to minimize involuntary hyperventilation immediately prior to a hypoxic set.
· Encourage swimmers to breathe as needed.
· Allow adequate time for recovery, which will vary from swimmer to swimmer.
Hypoxic Training - Underwater Drills Common underwater activities that can lead to SWB include repeated underwater swims or kicking drills as well as stationary breath holding competitions for time. In both instances, the nature of the risk is clear possible death. Even with successful resuscitation, complications including hypoxic brain damage and respiratory infection can occur.
With time, if underwater breath holding activities are allowed to occur it is likely that a swimmer will suffer a hypoxic blackout. Given that underwater breath holding activities resulting in SWB have led to death, the evaluation of the severity of this risk is catastrophic. Organizations would be well advised to eliminate the risk all together through a ban on underwater drills in all but a carefully and closely regulated environment.
In some cases, the Coaches may feel that underwater drills are necessary for skill improvements. If this this case the following risk reduction strategies should be in place:
· Instructor/coaches need additional experience and training before considering underwater drills.
· When swimming underwater, instruct swimmers to surface and breathe when necessary. Never resist the urge to breathe.
· Only allow one breath prior to submersion. SWB is closely linked to hyperventilation.
· Only allow underwater drills at the start of a workout when swimmers are not close to their maximum aerobic capacity (VO2 max).
· Only allow a distance of one length, one time. No repeats or challenges to see who can swim the greatest distance underwater.
· Allow adequate time for recovery, which will vary from swimmer to swimmer. A rule of thumb is to require a two-minute recovery time before attempting another underwater swim.
Dr. Alex Brothers Emergency Medicine / Sports Medicine
Swimming Canada National Team Physician
May 11th, 2017 - Sleep or Swim - The impact of training schedules on the sleep and fatigue of elite athletes
The objective of the study was to analyze the quantity and quality of sleep of elite athletes. Seventy athletes from seven sports were evaluated for two weeks through monitors, self-report logs and fatigue level before each workout. On average the athletes went to bed at 23:06 ± 01: 12h, woke up at 6:48 ± 01:30 h and slept 06:30 ± 01:24h. On the nights leading up to early morning workouts, the tendency was for athletes to sleep less. It was also found that with fewer hours of sleep the tendency was for fatigue before training was higher. Implications: Early morning workouts greatly affect sleep quality and fatigue levels. In cases where evening training will be unavoidable, preventive or compensatory measures (eg, going to bed earlier and avoiding factors that keep the athlete awake and vigilant or taking a mid-day nap) should be created.
The aims of the present study were to investigate the habitual sleep/wake behavior of elite athletes, and to compare the differences in sleep between athletes from individual and team sports. The main finding of this study was that on average athletes obtained 6.8 h of sleep per night. This amount of sleep was considerably lower than the 8 h of sleep per night necessary to prevent the neurobehavioral deficits associated with sleep loss (Belenky 2003; Van Dongen 2003). Athletes from individual sports obtained less sleep and had poorer sleep efficiency than athletes from team sports. The differences in training demands between individual and team sports may influence the amount and quality of sleep athletes obtain. For example, individual sports such as swimming, cycling and triathlon tend to have excessive training demands which often require athletes to complete multiple training sessions per day. While it is recognized that healthy fit individuals tend to sleep longer and have higher quality of sleep compared to their sedentary counterparts, there are data indicating that when athletes’ training demands are excessive the amount and quality of sleep may become disrupted. Although athletes from individual sports had poorer sleep efficiency and spent more time moving during sleep compared to athletes from team sports, the differences between sports were marginal and not considered clinically significant. The main disruption for sleep/wake behavior was that athletes from individual sports had significantly earlier bed and get-up times than athletes from team sports. The athletes from individual sports having early bed and get-up times were not surprising, given that the training sessions of individual sports examined within the present study typically started in the early hours of the morning ∼06:00 h. While there are limited physiological reasons why individual sports train early in the morning, the time between training sessions and access to facilities often dictate the timing of training. It is also recognized that early morning starts are a legacy from a time when nonprofessional athletes had to train before work or school. Athletes from individual sports went to bed earlier in preparation for a short sleep period as a result of their early get-up times. However, their bedtime was not early enough such that they obtained an average of 30 min less sleep compared to their counterparts from team sports.
Sleep monitoring may be a useful tool for support staff to identify athletes obtaining less than the general target of 8 h of sleep per night for healthy adults. Support staff may want to monitor sleep as it is a modifiable behavior such that coaches may be able to adjust the timing and/or scheduling of training in order to maximize the amount of sleep their athletes obtain, which may improve athletic performance.
“The study was supported by the Australian Research Council and the Australian Institute of Sport”
April 13th, 2017 - Sinking Legs When Swimming Freestyle?
Your legs sink when you swim freestyle? Do you have to kick hard to keep your legs from sinking when you swimming freestyle. Sinking legs when swimming freestyle is usually due to one of two things (or due to both things) - looking the wrong way or a weak core.
LOOKING UP OR FORWARD
Swimming with head too high: Try to always look straight down, with the very top of your head pointing where you want to go.
Get a feel for the right position by standing as straight as you can, use a very good posture, eyes looking forward. Imaging a line from the sky, through the top of your head, down your spine and down your legs to the ground. You want to keep that same line in the water and swim forward along it.
If you have a weak core you will bend in the middle. One end goes too low, the other tends to go to high; if your head is high in the water, your feet will tend to go low, unless you kick a lot to keep them up. Your upper body will tend to stay high in the water because of air in the lungs helping that part of the body to float like a filled balloon, and because you work to keep your head close enough to the surface of the water to get air when you need to take a breath.
Sometimes swimmers have to kick a lot to keep their body up and aligned. Nothing wrong with kicking, but you will spend a lot of energy. You can get more power out of your pull instead of relying on your kick.
Practice looking the bottom of the pool when swimming and looking to the side when you breath. Pay close attention to what you see while you swim, to help get your head in alignment with the rest of your body.
Think - good swimming posture, straight line head to feet - while swimming. That’s what we call in swimming a “good streamline”.
There are swim drills like the head point swimming drill. If you are seeing your destination while swimming, then you are looking up too much. If you see the bottom of the pool, then lane next to you, then the lane on the other side of you, you are swinging your head back and forth while you swim instead of keeping it still and aligned.
Weak core muscles: You may need to get stronger in the core section of your body, your belly, back, and sides. If you are not strong in the middle of your body, you can't hold your legs up, you fold around your belly and the legs sink. Strengthen your mid-section - all the way around, not just abs - should help.
Try to figure out if it is one, the other, or both head position and core strength. Once you know what to work on, you can get better at holding a good posture, legs up in the water, eyes looking down, top of your head leading the way while you swim.
March 23, 2017 - Do you have the need for Speed?
Water Polo: it’s a sport where fast swimming is important. Are you ready for speed training?
Sometimes, as athletes, frustration sets in because they cannot get as fast as they want in order to be the first ones to the ball, or to an open space (to receive a pass).
Let’s focus on the essentials required for increasing the speed of a swimmer. Is it more speed drills? Fewer intervals between sets? These are both good answers, but not necessarily the right ones.
Before building speed training, you should master your balance and technique. Speed work is worthless if you don’t have the right form in the water. You should master your balance from front to back, and from side to side. Your legs and hips shouldn’t sink, and your strokes should be even on both arms.
Try these drills by incorporating them into your daily routines, or even practicing them outside of the pool:
1. Swim with the left arm, breath to the left side, the right arm by your side (not out in front of you)
2. Swim with the left arm, breath to the right side, the right arm by your side (not out in front of you)
3. Swim with the right arm, breath to the left side, the left arm by your side (not out in front of you)
4. Swim with the right arm, breath to the right side, the left arm by your side (not out in front of you)
If it will make you more comfortable, start by practicing the arm and breathing motions whilst standing outside of the pool, or when standing in the shallow end of the water, bent over at the waist with your face down in the water.
When learning this drill, use fins to add support to your legs. These drills may be tough to get used to, and they will always be challenging to do, but they will help you tremendously with your balance.
Have you mastered your balance now? Now you’re ready for speed drills!
Feb 23rd, 2017 - The Flutter Kick
This time we are going to talk about the Flutter Kick. The first role of the flutter kick is to provide propulsion. While kicking is important in fast swimming. it might be less than you think. Studies have shown that the amount of propulsion provided by the kick in elite swimmers is only about 10%. The rest of propulsion is provided by the arm stroke. The second role of the flutter kick is to stabilize the body. This balance reduces the amount effort from your arms. In fact, the start of the propulsive phase of the arm stroke always coincides with a downward motion of the leg on the same side.
Let’s look at the flutter kick technique in more detail. The legs are kept parallel at all times and execute opposite movements: while one leg kicks downward the other one moves upward, and vice versa.
During the first half of the downbeat, the downward movement is initiated by slightly flexing the leg at the hip. Shortly after, the knee also bends a little bit. The foot goes in plantar flexion (toes pointed), both by muscle contraction and by the pressure of the water against the foot as it moves downward. During that phase, the top of the foot is oriented downward and a little bit backward. Because of this, while the foot moves down some water is in fact pushed back. That’s how propulsion is generated in the flutter kick.
During the second half of the downbeat, the hip is locked in place while the knee is extended. The toes are still pointed. This phase isn’t propulsive but prepares the leg for its upward movement.
The upbeat movement of the leg starts while the knee is still extending. In fact, while the leg moves upward, the pressure of the water against the lower leg will extend it. The pressure of the water against the bottom of the foot will also move it in an intermediary neutral position. This phase of the flutter kick isn’t propulsive either.
There are a few common mistakes in the flutter kick that decrease its efficiency and hence should be avoided:
-Large kick: to keep drag to a minimum, the kick should stay within the hole opened in the water by the head and trunk while moving forward. Ideally, the kick should neither break the water surface nor move below the line of the body.
·Bicycle kick: during the downbeat, the kick is initiated by slightly flexing the hip and then the knee follows, also only bending a little bit. If you bend the knee too much, the back of your lower leg will in fact move forward rather than upward. Water will then be pushed forward and slow you down.
·Putting too much force in the kick during the upbeat: in the freestyle stroke, the upbeat phase of the kick isn’t propulsive. So ideally you should relax your leg during the upbeat to save energy. This is a mistake it should be corrected at the beginner’s level and it rarely is.
· Bending your knee and pointing your toes during the upbeat: these two mistakes are closely related to the previous one. If you put too much force into the kick during the upbeat, you’ll also have the tendency to bend your knee and point your toes, which wastes energy and increases drag. Ideally you should relax your leg so that the water pressure will extend it during the upbeat.
·If you have stiff ankles, it might be that your foot is only oriented downward (to the bottom of the pool) during the first phase of the downbeat. If that’s the case, your kick might provide no propulsion at all or even have the tendency to move you backward rather than forward.
·Using swimming fins and/or stretching regularly can improve the flexibility of your ankles. Ankles are a very important part of a swimmer’s body and often are neglected when it come to increased flexibility or stretching.
·An excellent exercise to improve your kick is vertical kicking. The way you can find out if your flutter kick is efficient is making sure you stay in the same place when executing the vertical kicking. Keep your arms on the side closed to your legs, your head should be above water when you kick. You can increase the kick speed, doing that your shoulder should come to the surface.
February 2nd, 2017 - Your Skin and Swimming
Did you know our skin plays a very important role in the learning process of swim?
Yes, our skin has three layers and each layer contains the necessary receptors for the touch, thermal, pain, and pressure.
The Epidermis, the outermost layer of skin. Reacts by deformation to the act of touching (light touch). The Dermis, beneath the epidermis, contains thermal sensing receptors responsible for the cool and the heat sensations. The Hypodermis is a deeper subcutaneous tissue which contains receptors responsible for the feeling of light and strong pressure.
In swimming the sensations of contact, pressure and temperature plays a very important role in the learning process for the following reasons:
- The immersion in the water, when the water is not at a suitable temperature, conditions the staying time, therefore, delays the learning process.
- The information coming from the skin changes the breathing rate.
- The perception of the water pressure sensations in the limbs, in the aquatic path, should be developed, as information for the improvement of the gesture (stroke).