Summer is upon us and everyone is looking for ways to stay cool. The pool is a haven for most during the summer months to stay cool. Water splashing here and there, but have you thought about using the water for a place to get a workout.

Water resistance has long been used for rehabilitation, but what about using it for a regular resistance training workout. While I was in Korea recently, they had water resistance workout equipment as depicted in the picture above. Can a workout in the pool provide just as good of a workout as using resistance training equipment in the normal gym although?

A 2009 study published in the Journal of Strength and Conditioning Research looked at this and found the following results(1). The study used 12 fit young men in the study. During the 8 week study they used water devices that increased drag force.  After the eight week study they found a significant increase in upper body and leg power maximum strength and power. These results show that water resistance exercises can be used to produce improvements in muscular strength, power and reduction in fat mass.

Another interesting component of water resistance compared to normal resistance training in the gym is the amount of muscle damage that occurs. In another study that was also published in the same journal as above, they looked at the amounts of muscle damage when doing bicep curls and triceps extensions in the water compared to in a normal gym(2). When comparing the two environments, it was found that the water environment had much lower levels of muscle damage.

All of this to say that a good workout can even be achieved in water, just like in the gym, and might not produce as much muscle damage. So consider using the pool for a place to workout on a hot summer day when your muscles need some extra time to recovery. What type of exercises and apparatuses can you think of using in the pool for an effective workout? As long as you use proper technique and safe body mechanics, your imagination is the limit!

1Pantoja, PD, Alberton, CL, Pill, C, Vendrusculo, AP, & Kruel, LF. (2009). Effect of resistive exercise on muscle damage in water and on land. Journal of Strength & Conditioning Reseach, 23(3), 1051-1054.

2Colado, JC, Tella, V, Triplett, NT, & Gonzalez, LM. (2009). Effects of a short-term aquatic resistance program on strength and body composition in fit young men. Journal of Strength & Conditioning Research, 23(2), 549-559. 

Warm-up and Static Stretching Is a Common Routine Prior to Performance:
Stretching as part of warm up is commonly integrated as part of the pre-competition routine for competitive athletes and recreational fitness participants in order to reduce injury and improve muscular performance. Previous recent research ¹ suggests that acute stretching before maximal muscular performance may hinder the ability of the muscle to produce force.  Two theories to explain this include mechanical factors such as reduced stiffness on the musculotendinous unit and/or neural factors such as altered motor control or a greater autogenic inhibition.¹ However, this study investigated stretching volume, rest interval, and stretching method effects on the 1 Repetition Max bench press in resistance trained collegiate football players.

It was thought that static stretching would be detrimental to 1 RM performance. The investigators proposed that high volume static stretching (HVSS) and high volume Proprioceptive Neuromuscular Facilitation (HVPNF) stretching would have a significant detrimental effect on 1 RM bench press because of repeated high volume placed on the muscle.  A within–subject randomized repeated measures design was used. Fifteen athletes completed 5 different stretching protocols integrated with a 1RM dynamic warm-up routine followed by 1RM bench press testing in randomly assigned order.

5 Stretching Protocols:
The protocols included a) non-stretching (NS), b) low-volume  PNF stretching (LVPNFS), c) HVPNFS, d) low-volume static stretching (LVSS), and e) HVSS. The two stretches selected were the chest/shoulder partner stretch, and the overhead triceps partner stretch.

Types of Subjects and Conditions Important for Study Selection:
All of the subjects were injury free and able to perform stretching exercises and the 1RM bench press test without pain.  Furthermore none of the subjects had taken creatine or other performance-enhancing substances within the previous 90 days. Subjects refrained from vigorous upper body exercise for 48 hours before each testing session. Anthropometric measurements were taken before testing and the 3 site skin folds for body composition (chest, abdomen, thigh) and body weight to the nearest 10th of a kilogram.  The strength testing protocol was the American College of Sports Medicine guidelines for the Bench Press 1 RM.  The subjects assumed a supine position on a bench with the feet flat on the ground, the grip on the bar at slightly wider than shoulder width and the bar lowered to the chest in a smooth, controlled manner and lifted to a maximal upper limb length.

Results:
One way ANOVA analysis showed that there was no significant effect of any of the 5 stretching treatments on the 1 RM bench press performance.  Furthermore, repeated measures ANOVA revealed no significant differences among the testing days which indicates there was no testing order effects.  So, while the investigators expected a detrimental effect on the 1 RM results, no negative effects were determined. However, the rest interval after the stretching session and prior to the initial 1 RM attempt was 5 minutes.  This time interval may have been sufficient time to mitigate the effects of the stretching protocols on muscular performance.  This was consistent with the findings reported by Torres et al. ² on upper body performance by collegiate track throwers with 5 minutes of rest after stretching. 

Discussion:
This study and most comparative studies had trained collegiate athletes as subjects that performed regular stretching as part of the training warm-up routine and suggests that they have developed an adaptation of recovering from altered elastic properties of the musculotendinous unit within the 5 minutes of rest. Also, previous studies that reported decrements in performance was mostly studied in the lower body (Achilles tendons, hamstrings, calves) and suggest that acute stretching in the upper body may respond differently to acute stretching in the lower body. 

Student Questions:
1) Do you see how trained athletes versus untrained subjects might get different results?  There seems to be an adaptation to a set routine and regular warm-up and strength training.
2) What does the Law of Specificity have to do with this?
3) If you were conducting a follow up study, what would you alter to test subjects and get different results?

¹Zachary D. Molacek, Donovan S. Conley, Tammy K. Evetovich, and Kristi R. Hinnerichs. Effects of Low-and High-volume Stretching on Bench Press Performance In Collegiate Football Players. Journal of Strength and Conditioning Research 24:711-716, 2010.
²Torres, EM, Kraemer, WJ, Vingren, JL, Volek, JS, Hatfield, DL, Spiering, BA, Ho,JY, Fragala, MS, Thomas, GA, Anderson, JM, Hakkinen, K, and Maresh, CM. Effects of stretching on upper-body muscular performance. Journal of Strength and Conditioning Research 22:1279-1285,2008.

What if you could burn calories faster while strength training? A recent study¹ compared the calories burned during two types of strength training workouts - traditional and superset. Traditional involves completion of one set of repetitions for a specific exercise followed by an inactive rest period. Superset training works two opposing muscle groups before taking a recovery period. Working opposing muscle groups allows the first muscle to rest while the opposing muscle group is working.  

The study measured calories burned during the two types of resistance training. Ten active men (average age 22 years and 165 pounds) completed a superset workout and a traditional workout on different days using the same resistance while performing the same exercises. Each workout exercised six muscle groups (chest, back, and the anterior and posterior muscles of the arms and thighs). Subjects completed four sets of each exercise lifting 70% of their 1 Repetition Maximum (1 RM). During the superset workout, subjects completed two back to back exercises for opposing muscle groups (for example, chest and back) followed by a 60 second rest before repeating the same two exercises three more times. For the traditional workout, subjects performed one set of an exercise followed by a 60 second rest before repeating that exercise three more times. The traditional workout had twice as many rest periods as the superset workout. Therefore, the traditional workout took longer to finish than the superset workout (30 vs 36 minutes). 

Researchers measured the total calorie burn during the workout, calories burned per minute, and the extra calories burned during 60-minutes of recovery. The total calorie burn during the superset workout was 241 calories while the traditional workout totaled 227 calories. Due to the fewer rest periods during the superset workout, subjects averaged 8.0 calories per minute and the traditional workout averaged 6.3 calories per minute. During the 60 minutes of recovery, the superset workout burned an extra 19 calories compared to the traditional workout which burned 14 calories above baseline resting caloric expenditure.

The take home message is that both types of strength training programs provide similar calorie burn for the same volume (sets x reps x weight) of exercise. But, for those who want to burn the most calories in the shortest amount of time, superset strength training programs provide the biggest bang for your buck at 8.0 calories per minute. Maybe its time to rethink your current resistance training program and switch to supersets; you could cut your workout time by 17% and spend the extra time on cardio exercises like cycling or running to burn an additional 50-75 calories depending on the intensity. Are you wasting precious workout time that could be better spent burning calories?                

1. Fairchild, T. J., Hackney, K. J., Kelleher, A. R., Keslacy, S., and Ploutz-Snyder, L. L. (2010). The metabolic costs of reciprocal supersets vs. traditional resistance exercise in recreationally active adults. The Journal of Strength and Conditioning Research, 24(4), 1043-1051. 

Does Exercise Make Us Hungry?

There has been much debate about the effect of exercise on appetite and energy intake.  Although some scientists have proposed that exercise stimulates appetite; most studies do not support this finding. 

A recent study published in Medicine & Science in Sports & Exercise⁴ examined the effect of walking on appetite and food intake.  In the study, subjects participated in two different trials – an exercise and a nonexercise (control) trial.  One day subjects walked for 60 minutes on a treadmill with some mild shortness of breath but were still able to hold a conversation.  On another day, they came to the lab at the same time of day but did not exercise (control trial).  Subjects were offered an “all you can eat” buffet style meal two hours after exercise and again at five hours after exercise. When subjects did not exercise they were offered the same buffet meal at the same time of day.  Subjects also rated their appetite every 30 minutes.

The results showed that after a 60-minute brisk walk subjects did not increase the amount of food they ate for the next seven hours compared to the control trial.  In fact, exercising subjects had a 439 calorie deficit after accounting for the amount of food consumed.  There was also no difference in the fat or carbohydrate content of meals on the exercise vs. nonexercise days.  Researchers also measured levels of a hormone (ghrelin) produced in the stomach which is known to increase hunger.  They found no difference in the hormone levels or ratings of appetite on the exercise compared to nonexercise trials. 

This study supports the findings of other researchers¹ that moderate intensity exercise does not increase appetite.  With regard to high intensity aerobic exercise, studies^2,3 tend to show that appetite is suppressed for a brief period after 60 minutes of treadmill running.  Another study² also reported a brief suppression of appetite after 90 minutes of resistance training. 

Dieting alone to lose weight can be brutal.  So why not go for a bigger calorie deficit by adding exercise to your diet program.  Exercise yields lots of health benefits like improvements in blood pressure, cholesterol, and blood sugar levels.  Plus, exercisers have lower all-cause death rates.  It's time to get moving!     

1.  Blundell, J.D., and King, N.A. (2000). Exercise, appetite control, and energy balance. Nutrition, 16(7-8), 519-522.

2.  Broom, D.R., Batterham, R.L., King, J.A., Stensel, D.J., Batterham, F.L., and King, J.A. (2009). Influence of resistance and aerobic exercise on hunger, circulating levels of acylated ghrelin, and peptide YY in healthy males. Am J Physiol Regul Integr Comp Physiol, 296(1), 29-35.

3.  Broom, D.R., Stensel, D.J., Bishop, N.C., Burns, S.F., and Miyashita, M. (2007). Exercise-induced suppression of acylated ghrelin in humans. J Appl Physiol, 102(6), 2165-71.

4. King, James A., Wasse, L.K. Broom, D.R., and Stensel, D.J.. (2010) Influence of brisk walking on appetite, energy intake, and plasma acylated grehlin. Med & Sci in Sports & Exerc, 42(3), 485-492.

Researchers are discovering that resistance training in overweight and obese children and adolescents is having multiple positive effects.  For starters it is increasing their time spent in physical activity.  It is lowering their body fat, improving their bone density, and increasing their sensitivity to insulin.¹ But, there is more. In a 16 weeks study in which youth participated in progressive resistance training, there was also a 96% adherence rate.² This is key because identifying activities that they like and can excel in is important for our youth to adopt a lifestyle of regular physical activity.

Also psychosocial wellbeing was improved.  Part of this is attributed to the growing confidence youth had because of their improved motor skill performance.  In other words, overweight and obese children and adolescents tend to have low motor abilities due to little participation in physical activities.³ This in turn negatively affects their confidence.  Without confidence there is less chance they will try other activities or even engage in physical activity.  But in resistance training programs, overweight and obese youth shine and even excel.  They tend to be the strongest students in the class, and they often receive positive feedback from their normal weight peers who are impressed with the amount of weight they can lift for the prescribed number of repetitions. 

Furthermore, these at risk youth tend to get bored with cardiovascular activity or it brings discomfort to them.  However, with resistance training which is characterized by short periods of physical activity followed by a brief rest period between sets and reps, the youth are enjoying it and sticking with it.

The following are some of the guidelines for resistance training for youth:⁴
• Provide qualified instruction and supervision
• Children as young as 7-8 years old may participate
• Begin each session with 5-10 minutes of warm up
• Start with 1 light to moderate set of 10-15 repetitions
• Progress to 2-3 sets of 6-15 reps
• Focus on the correct technique rather than the amount of weight lifted
• Train 2-3 times per week on non consecutive days
• In general, adolescents require 1-2 minutes recovery between sets; children as little as 1 minute recovery
• Keep the program fresh and challenging by systematically varying the training program
• Cool down with less intense activities and stretching

Finally, there was not one optimal number of set, reps, and weight.  Instead, the emphasis should be to create safe, progressive, programs with regular variations to keep sessions fresh and challenging.  Also, any variety or combination of exercise equipment like small apparatus or children’s’ resistance training machines can be used.  And of course positive support and close supervision will make the programs successful.

1Faigenbaum A. Resistance training for children and adolescents: Are there health outcomes? Am J Lifestyle Med. 2007;1:190-200.

2 Shaibi GQ, Cruz ML, Ball GD, Weigensberg MJ, Salem GJ, Crespo NC, Goran MI. Effects of resistance training on insulin sensitivity in overweight Latino adolescent males. Med Sci Sports Exerc.2006:38:1208-1215.

3 Stodden D, Goodway J, Langendorfer S, Robertson M, Rudisill M, Garcia C, Garcia L. A developmental perspective on the role of motor skill components in physical activity: An emergent relationship. Quest. 2008; 60:290-306.

4 Faigenbaum A, Westcott W. Youth Strength Training: Programs for Health, Fitness and Sport. Champaign, Il: Human Kinetics, 2009.