To play or not to play

We have spent a lot of time and attention discussing the merits of being active.  No one will disagree that being active is better than being inactive.  (Any couch potatoes out there who disagree?).  So the question becomes “Should we, and if so, when should we, start children on a skill development program?”  The argument is that if a child is more skilled at something than they are more likely to do it and make a habit of it.  So how do we find out what skill or activity at which the child excels physically, cognitively, and emotionally? 

Think of all the different activities out there. How many team sports are there available to children? How many individual sports? How many non-competitive activities? How many activities where the child can just run, and jump, and play….you know, be a kid. 

One way that is fast becoming extinct is for parents to play with their children rather than shuffling them off to the “next activity”.  I am amazed at how many parents drop the kids off somewhere as they do their errands, shopping, etc.  After soccer, it’s off to karate, or baseball, or basketball, the list goes on. 

The United Nations High Commission for Human Rights states that every child has the right to play (Ginsberg, 2007) .When a parent plays with their child, the child develops creativity, imagination, dexterity, and physical, cognitive, and emotional strength. Play time helps enhance the academic setting by attending to social and emotional needs. Undirected play allows a child to learn to share, communicate, and resolve conflicts while too much “adult organized” activity causes a loss of creativity, and loss leadership and group skills (Ginsberg, 2007).  Adult directed activity places undue burdens and expectations on many children who may not be able to live up to their parents wishes.  When a parent plays with a child, they can see where the child excels or has no interest or skill without extensive genetic, physical, or cognitive tests.  Simple “playtime” may be the best answer for determining in what activities children should participate.

In a 2009 New York Times article (Parker-Pope, 2009), it is suggested that 15 minutes of recess improved classroom behavior and is as important as the directed academics.  The article goes on to state that the Journal of School Health reported that children involved in physical activity during gym class performed better on tests than their sedentary counterparts.  The solution - let them play and use their imaginations; let them join in on a pick up game of any sport; throw a ball or a Frisbee with them.  Please, just let kids be kids as it will help them academically. 

Ginsberg, K.  (2007)  The importance of play in promoting healthy child development and maintaining strong parent-child bonds.  Pediatrics 116(1), 182-191. 

Parker-Pope, T. (2009). The 4 r's? A fourth is crucial, too: Recess. The New York Times, February 24, 2009. Retrieved from http://www.nytimes.com/2009/02/24/health/24well.html?_r=1&scp=1&sq=recess&st=cse on April 17, 2009.

Cardio – Before or after?

One of the most frequently asked questions I get regarding cardio is whether it should be done prior to or after resistance weight training.  First let me say that I am not a huge fan of doing cardio and weights during the same workout.  It’s too easy to think that since I am going to be doing more, I do not have to exert on the first portion of the workout.  Or, since I have already exerted so much for the first part, I can slack a little on the second. Experience tells me that one or the other will suffer.  I know that not everyone has the time to do this, but I prefer doing cardio and resistance training on separate days so I can put full effort into each; if not separate days, at least a few hours apart.   If you must do both on the same day, do resistance weight training first and then cardio.

Many studies have reported that concurrently performing strength training and endurance training will compromise strength and power (Chromiak & Mulvaney, 1990).  Rhea et al. (2008) studied the effects of plyometric training with concurrent cardiovascular endurance training on collegiate baseball players.  One group performed a combination of plyometrics and endurance while another group performed just plyometrics.  The combined group decreased in speed and power while the single group showed an increase in speed and power.  Nader (2006) suggests that this phenomenon, known as the interference phenomenon, is because certain enzymes that are needed for strength gains are mitigated by endurance training. 

Now for the physiology; the body utilizes three energy systems. The phosphagen system uses adenosine triphosphate (ATP) and creatine phosphate (CP) as fuel.  The glycolytic system is when glycogen (sugar) from the muscle or glucose (sugar again) from the blood is converted to ATP and used as fuel.  The oxidative system resynthesizes carbohydrates and fat into ATP.  The phosphagen system only supplies energy during short bursts that last for just a few seconds.  The glycolytic system lasts just a few minutes and the oxidative system is used for exercise durations longer than three minutes. 

The three energy systems of the body, phosphagen, glycolytic, and oxidative, work together and often overlap, however as mentioned, endurance training (aerobic) and strength training (anaerobic) will often elicit incompatible results.  Rhea et al. (2008) propose a fitness continuum that consists of neuromuscular power, muscular strength, muscular endurance, and cardiovascular endurance.  Training for the individual components in the fitness continuum will result in differing physiological outcomes.  It is also thought that the closer the components are in the continuum, the more compatible the training adaptations will be.  Similarly, the further apart the components are in the continuum, the less compatible the adaptations will be. 

In theory, to move into the oxidative system, you need to pass through the phosphagen (ATP-CP) and glycolytic (sugar) systems.  This leaves too little of the proper fuel for resistance weight training.  Where as performing strength exercises first and depleting the first two energy systems, one is ready to move into the oxidative system.  Bottom line, do strength training first and then cardio. 

Chromiak, J. & Mulvaney, D. (1990). A review: The effects of strength and endurance training on strength development.  Journal of Applied Sport Science Research, 4(2), 55-60.

Nader, G. (2006). Current strength and endurance training: From molecules to man. Medicine and Science in Sports and Exercise. DOI: 10.1249/01.mss.0000233795.39282.33. 

Rhea, M., Oliverson, J., Marshall, G., Peterson, M., Kenn, J., Naclerioayllo’n, F. (2008).  Noncompatibiality of power and endurance training among college baseball players.  Journal of Strength and Conditioning Research, 22(1), 230-234. 

High or Low Intensity for Cardio?

Have you ever looked at the chart on the cardio equipment that has the different training zones?  You’ll see a range for endurance, one for fat burning, and one for whatever....  Why is it that the fat burning zone requires less intensity than the aerobic capacity training zone?

The number is based on percentage.  In other words, training at a less intense pace, you will burn more fat - percentage wise - than training at a higher intensity.  However, let’s break these numbers down. 

The following is a comparison of energy expenditure between 30-40 Minutes of Low-Intensity vs. High Intensity Exercise

Low intensity:

Calories burned – 200

% Fat calories – 50%

Total Fat Calories-100

% of Carbohydrate calories-50%

Total Carb calories – 100

Calories per minute-6.67

High intensity:

Calories burned – 400

% Fat calories – 30%

Total Fat Calories-120

% of Carbohydrate calories-70%

Total Carb calories – 280

Calories per minute-13.5

Tell me, which numbers would you prefer? 

The American College of Sports Medicine and U.S. Surgeon General suggest that a minimum of 30-60 minutes of moderate activity be performed most days of the week to reduce the risk of cardiovascular disease.

2008 Physical Activity Guidelines for Americans (DHHS)

• Adults, 18-64: should avoid inactivity. Some physical activity is better than none, and adults who participate in any amount of physical activity gain some health benefits.

• For substantial health benefits, adults should do at least 150 minutes a week of moderate-intensity, or 75 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic activity.
• Aerobic activity should be performed in episodes of at least 10 minutes, and preferably, it should be spread throughout the week.
• For additional and more extensive health benefits, adults should increase aerobic physical activity to 300 minutes a week of moderate-intensity, or 150 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity activity.
• Additional health benefits are gained by engaging in physical activity beyond this amount.
• Adults should also include muscle-strengthening activities that involve all major muscle groups on 2 or more days a week.