Del P. Wong

Publications (92) View all

• Source

  Available from: Monoem Haddad

  Article: Effects of ramadan on the diurnal variations of repeated-sprint performance.

  Asma Aloui, Anis Chaouachi, Hamdi Chtourou, Del P Wong, Monoem Haddad, Karim Chamari, Nizar Souissi
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  ABSTRACT: Purpose: This study examined the effects of Ramadan on cycling repeated-sprint ability (RSA) and corresponding diurnal variations. Methods: Twelve active men performed an RSA test (5 × 6-s maximal sprints interspersed with 24 s passive recovery) during morning and afternoon sessions 1 wk before Ramadan (BR), during the second (R2) and the fourth (R4) weeks of Ramadan, and 2 wk after Ramadan (AR). Maximal voluntary contraction was assessed before (MVCpre), immediately after (MVCpost), and 5 min after the RSA test (MVCpost5). Moreover, hematocrit, hemoglobin, and plasma sodium and potassium (K+) concentrations were measured at rest and after the RSA test and MVCpost. Results: Overall, peak power (Ppeak) during the RSA test decreased throughout the 5 sprints. Ppeak measured in the first sprint and MVCpre were lower during Ramadan than BR in the afternoon (P < .05) and higher in the afternoon than the morning BR and AR (P < .05). However, this diurnal rhythmicity was not found for the last 4 sprints' Ppeak, MVCpost, and MVCpost5 in all testing periods. Furthermore, the last 4 sprints' Ppeak, MVCpost, MVCpost5, and morning MVCpre were not affected by Ramadan. [K+] measured at rest and after the RSA test and MVCpost were higher during Ramadan than BR in the afternoon (P < .05) and higher in the afternoon than the morning during Ramadan (P < .05). Conclusions: Fatigability is higher in the afternoon during Ramadan, and, therefore, training and competition should be scheduled at the time of day when physical performance is less affected.
  International journal of sports physiology and performance 05/2013; 8(3):254-62. · 1.80 Impact Factor
• Source

  Available from: Monoem Haddad

  Article: Static Stretching Can Impair Explosive Performance For At Least 24 Hours.

  Monoem Haddad, Amir Dridi, Chtara Moktar, Anis Chaouachi, Del P Wong, David Behm, Karim Chamari
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  ABSTRACT: The aim of this study was to compare the effects of static versus dynamic stretching on explosive performances and repeated sprint ability (RSA) following a 24-h delay. Sixteen young male soccer players performed 15-min of static stretching (SS), dynamic stretching (DS), or a no stretch control condition (CC) 24-h before performing explosive performances and RSA tests. This was a within-subject repeated measures study with SS, DS, and CC being counterbalanced. Stretching protocols included 2 sets of 7-min 30-sec (2 repetitions of 30-sec with 15-sec passive recovery) for five muscle-groups (quadriceps, hamstring, calves, adductors, and hip flexors). 24-h later (without any kind of stretching in warm up), players were tested for 30-m sprint test (with 10- and 20-m lap-times), 5 jump-test (5JT), and RSA test. Significant differences were observed between CC, SS and DS with 5JT (F=9.99, p<0.00, ES=0.40), 10m sprint time (F=46.52, p<0.00, ES=0.76), 20m sprint time (F=18.44, p<0.000, ES=0.55) and 30m sprint time (F=34.25, p<0.000, ES=0.70). The significantly better performance (p<0.05) was observed after DS as compared to CC and SS in 5JT, and sprint times for 10m, 20m and 30m. In contrast, significantly worse performance (p<0.05) was observed after SS as compared to CC in 5JT, and sprint times for 10m, 20m and 30m. With RSA, no significant difference was observed between different stretching protocols in total time (F=1.55, p>0.05), average time (F=1.53, p>0.05), and fastest time (F=2.30, p>0.05), except for the decline index (F=3.54, p<0.04, ES=0.19). Therefore, SS of the lower limbs and hip muscles had a negative effect on explosive performances up to 24-h post-stretching with no major effects on RSA. Conversely, DS of the same muscle groups are highly recommended 24-h before performing sprint and long-jump performances. In conclusion, the positive effects of DS on explosive performances seem to persist for 24-h.
  The Journal of Strength and Conditioning Research 04/2013; · 1.83 Impact Factor
• Article: Effect of an Injury Prevention Program on Muscle Injuries in Elite Professional Soccer.

  Adam L Owen, Del P Wong, Alexandre Dellal, Darren J Paul, Emmanuel Orhant, Stuart Collie
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  ABSTRACT: Due to the continual physical, physiological and psychological demands of elite level soccer increasing the incidence and risk of injuries, preventative training programs have become a common feature of soccer players training schedule. The aim of the current investigation was to examine the effectiveness of a structured injury prevention program on the number of muscle injuries as well as the total number of injuries within elite professional soccer. The present study was conducted over two consecutive seasons, of which the first (2008-2009) being the intervention season and the second the control season (2009-2010). In total, 26 and 23 elite male professional soccer players competing within the Scottish Premier League and European competition participated. The training programme was performed twice weekly for the entirety of the season (58 prevention sessions). The results revealed an increase in the total number of injuries within the intervention season (88 vs. 72), however this was largely due to the greater number of contusion injuries sustained within the intervention season (n=44) when compared to control season (n=23). Significantly less muscle injuries were observed during the intervention season (moderate effect) and this occurred concomitant with a bigger squad size (large effect, p<0.001). The findings from this study identify a multi component injury prevention training program may be appropriate for reducing the number of muscle injuries during a season but may not be adequate to reduce all other injuries.
  The Journal of Strength and Conditioning Research 03/2013; · 1.83 Impact Factor
• Source

  Available from: Andrew (Drew) Smith

  Article: Using Bench Press Load to Predict Upper Body Exercise Loads in Physically Active Individuals

  Del P. Wong, Kwan-Lung Ngo, Michael A. Tse, Andrew W. Smith
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  ABSTRACT: This study investigated whether loads for assistance exercises of the upper body can be predicted from the loads of the bench press exercise. Twenty-nine physically active collegiate students (age: 22.6 ± 2.5; weight training experience: 2.9 ± 2.1 years; estimated 1RM bench press: 54.31 ± 14.60 kg; 1RM: body weight ratio: 0.80 ± 0.22; BMI: 22.7 ± 2.1 kg·m -2) were re-cruited. The 6RM loads for bench press, barbell bicep curl, overhead dumbbell triceps extension, hammer curl and dumb-bell shoulder press were measured. Test-retest reliability for the 5 exercises as determined by Pearson product moment correla-tion coefficient was very high to nearly perfect (0.82-0.98, p < 0.01). The bench press load was significantly correlated with the loads of the 4 assistance exercises (r ranged from 0.80 to 0.93, p < 0.01). Linear regression revealed that the bench press load was a significant (R 2 range from 0.64 to 0.86, p < 0.01) predictor for the loads of the 4 assistance exercises. The following 6RM prediction equations were determined: (a) Hammer curl = Bench press load (0.28) + 6.30 kg, (b) Barbell biceps curl = Bench press load (0.33) + 6.20 kg, (c) Overhead triceps extension = Bench press load (0.33) -0.60 kg, and (d) Dumbbell shoulder press = Bench press load (0.42) + 5.84 kg. The difference be-tween the actual load and the predicted load using the four equations ranged between 6.52% and 8.54%, such difference was not significant. Fitness professionals can use the 6RM bench press load as a time effective and accurate method to predict training loads for upper body assistance exercises.
  Journal of sports science & medicine 03/2013; 12(1):38-43. · 0.75 Impact Factor
• Source

  Available from: Andrew (Drew) Smith

  Dataset: Wong - Using bench press load to predict - 2012

  Del P. Wong�, Kwan-Lung Ngo, Michael A. Tse, Andrew W. Smith