Physiological demands of the Absa Cape Epic mountain bike race and predictors of performance.
The purpose of the study was to determine the exercise intensity of the actual competion (ABSA Cape Epic). Exercise intensity profiling of actual competitions can be useful to understand the physiological demands of these particular cycling events. From a practical point of view, this information will also help to design proper training programs. Furthermore, as many coaches include some races as part of training, the exercise-intensity profile could be useful to understand the training load imposed on athletes. This information can be used to ensure proper training intensities for efficient training adaptation, but also to prevent overtraining. The main findings of this study were that the men and women in the study sample did not differ from each other in physiological characteristics or in performance outcomes in the laboratory. Therefore all the participants where pooled and divided into a novices and experienced group according to their MTB experience. The two groups didn’t differ in physical or physiological characteristics and performance outcomes in the laboratory.
Except for the higher blood lactate response during the TT by the experienced group. The experienced group performed better during the event than the novice group in both the final event time and general classifications category. The experienced group spent statistically significantly more time in the “moderate” HR zone and a greater percentage of time in the “high” HR zones than the novices group. It was also found that there was a decrease in maximal HR obtained in the field from the first day of the event to the last. The same happened for the average stage HR and the percentage time spent in the hard HR zones (80-90% and 90-100% of maximal HR) for both groups. Absolute and relative PO at OBLA showed the strongest correlations to event performance. Low correlations were found between the laboratory variables and average HR during the event, showing that it is not possible to predict the HR response during an event from laboratory variables. Lastly, the correlations found between the laboratory TT variables and event performance was not high and therefore the use of the maximal aerobic test to determine predictors of performance is sufficient.
OPSOMMING VAN M: The effect of plyometric training on the performance of cyclists
Die doel van die studie was om te bepaal wat die effek van pliometriese oefeninge is op die aërobiese en anaërobiese vermoëns van goed ingeoefende fietsryers.
Twintig kompeterende mans fietsryers, (ouderdom: 24 ± SD 5 jaar, lengte: 180 ± SD 6 cm en gewig: 77 ± SD 6 kg), was ewekansig ingedeel in of ‘n eksperimentele (n = 13) of ‘n kontrole groep (n = 7). Die groep sluit twaalf bergfietsryers en agt padfietsryers in. Kinantropometriese metings, vertikale spronghoogte, ‘n bolyf kragtoets (“bench pull test”), ‘n maksimale aërobiese uithouvermoë toets, ‘n binneshuise 5-kilometer tydtoets (TT), ‘n anaërobiese kapasiteit toets (30-sekonde Wingate toets) en ‘n buitemuurse 4.4-kilometer tydtoets (veldtoets) was voltooi gedurende die toetsperiode.
Die pliometriese oefenprogram het geen statisties betenisvolle effek op maksimale aërobiese kapasiteit, anaërobiese kapasiteit, tydtoets prestasie (laboratorium en veld) of op vertikale spronghoogte van die eksperimentele groep gehad nie. Spesifieke uitkomsveranderlikes, soos VO2maks, piek en gemiddelde kraguitset gedurende die Wingate toets, en die tyd wat dit geneem het om die laboratorium tydtoets te voltooi, het gegrens aan ‘n statistiese betekenisvolle verbetering in die eksperimentele groep. Die eksperimentele groep het ‘n betekenisvolle verbetering getoon in hul bolyfkrag na die intervensie. Daar was ook ‘n sterk verband tussen die veld tydtoets en die bolyfkrag in die eksperimentele groep (r = 0.72).
Hoewel die pliometriese oefenprogram nie die prestasie van die fietsryers betekenisvol verbeter het nie, het dit tekens van verbetering in die eksperimentele groep se anaërobiese en bolyfkrag getoon. ‘n Vorige studie het voorgestel dat ‘n pliometriese inoefeningsprogram slegs na ‘n paar weke na die intervensie ‘n effek sal toon in prestasie. Daarom is dit moontlik dat die fietsryers in die studie die voordele van pliometriese oefeninge eers later ervaar het, nader aan die kompetisiefase wanneer die doel van die oefenprogram is om spoed en krag te verbeter.
HUIDIGE POSISIE: Ek is tans ‘n bestuurder by Maties Sport. Verder is ek hierdie jaar besig om my MBA te voltooi by Stellenbosch Universiteit se Besigheidskool.
GUNSTELING HERINNERINGE VAN DIE LAB: My gunsteling herinneringe by die lab sluit in al die toetse wat ons gedoen het met van ons land se beste atlete. Verder al die lekker geselskap, grappe en poetse wat ons op mekaar gebak het. Laaste maar nie die minste nie, Prof Terblanche se mentorskap wat ‘n groot invloed op my persoonlike groei gehad het.
I’m currently an assistant lecturer at the Department of Sports and Exercise Science at Kwame Nkrumah University of Science and Technology.
The study investigated the effect of high intensity interval training (HIIT) on the post-exercise hypotensive response in overweight/obese young women.
Twenty overweight/obese young women were recruited in the study. The participants performed six sessions of HIIT within two weeks and detrained for two weeks. SBP, DBP, and HR were monitored during seated recovery after exercise for 60 min after an acute (first HIIT session) session and the after completion of the six HIIT sessions as well as during detraining from exercise intervention to determine the change from resting values.
The results indicate that both an acute bout and six sessions of HIIT elicited a meaningful PEH response. However, the six sessions of HIIT caused a clinically significant reduction which was approximately twice the acute session. Likewise, detraining showed clinically significant effects in DBP, but SBP returned to near baseline values. This suggests that in only two weeks, the accumulated effects of six sessions of HIIT elicited a greater hypotensive response than after an acute session of HIIT.
Research Study: The effects of water immersion on the recovery and performance of competitive cyclists.
The objective if the study was to determine whether water immersion (cold vs. neutral) has any effects on the post-exercise recovery rate of cyclists during three days of intensive endurance training and whether recovery with water immersion is more effective than active recovery.
Seventeen competitive cyclists (mean +- SD: age: 27.6 +- 5.94 years; PPO: 352.6 +- 35.94 Watts; VO2max: 49.8+-4.13 L/min/kg) completed 3 days of intensive endurance cycling sessions. Cyclists were randomly assigned to either a 20 minutes ice bath (IB) (n = 6, 11+- 0.9 Degree Celsius), neutral bath (NB) (n = 6, 30 +- 0.6 Degree Celsius) or active recovery (AR) (n = 5, 81 +- 1.74% of Lactate threshold Heart Rate), which were performed directly after the training sessions on day 1 and day 2. Dependent variables such as anaerobic performance, creatine kinase [CK], c-reactive protein [CRP] , and blood lactate concentrations [La], muscle soreness, perceived fatigue, and limb circumferences were measured prior to training sessions at day 1, 2 and 3. Changes in exercise performance over the last 2 days were also assessed.
No treatment or interaction effects were observed for any of the dependent variables for any of the recovery interventions (P > 0.05). Blood [La] was significantly reduced on day 2 for the IB group in comparison to the NB group (P < 0.05). A strong tendency was observed for [CK], when the IB and NB groups were combined (Water Group), indicating that AR had a strong tendency to enhance the recovery of [CK] in comparison to WG (P = 0.05).
These finding suggest that neither cold water, nor neutral water immersion therapy, have more beneficial effects on post-exercise recovery rates compared to active recovery. Importantly, however, is that cyclists’ were able maintain their performances over three consecutive days, indicating that water immersion per se is not detrimental to endurance performance.
Current Position: Studying Biokinetics honors, work as a cycling coach for 3 years
Memories van die lab: Mens kan altyd doen met nog n koppie koffie …. Saam met..toe…Karen Welman (tans Dr. Welman).
Lekker lag en musiek hard speel saam met Ludwig.. Goeie inspirasie vir die wat maksimale toetse kom doen het.
Ginos pizza was ons gunsteling “meeting plek”…vir werk bespreek..
Sal ook nooit vergeet toe die berg agter die sport wetenskap gebou besig was om af te brand, was ek nog besig om ‘n ou te toets op die kingcycle vir my meesters. Die vlamme was al teen die glas van die vensters aan die agterkant van die rehab swembad, maar my proefpersoon was vasberade om sy tydtoets klaar te trap. Naderhand het Ludwig ingehardloop gekom en geskree ek moet stop en die rekenaars red uit die lab, die plek gaan afbrand. Ek het nog nooit so vinnig opgpak en rekenaars vanuit die lab ontvoer nie.. dit was hectic.
Aletta Esterhuyse Millen
Research Study: Die effek van land en water oefening op die akute bloeddruk response
Die land oefening het bestaan uit ‘n kombinasie van matige aerobiese oefening en lae intensiteit weerstand oefening. Die water oefening was ‘n “water aerobics” sessie. In vergelyking met ‘n kontrole behangedling (geen oefening) het beide die water en land oefening ;n beduidende verlaging in bloedrruk veroorsaak vir minstens 9 uur na die oefening. Die land oefening het egter ‘n langer daling in bloeddruk van tot 24 uur veroorsaak. Dus het ek gevind dat beide land en water oefeninge voordelig en veilig is vir die verlaging in bloeddruk in the 24 uur na oefening in persone met hoë bloeddruk
Huidige posisie: Na haar Meesters het Aletta haar PhD voltooi by die Mediese Fisiologie departement (School of Physiology, Faculty of Health Sciences) by die Universiteit van die Witwatersrand. Sy is tans steed ‘n dosent by die Fisiologie Skool by Wits.
Gunsteling lab herinnering: Ek het wonderlike ervaringe gehad op Stellenbosch, veral in die Oefen fisiologie lab. Ek het wonderlike vriende gemaak, en veral die mense daar sal my vir ewig by bly, veral Prof Terblanche se raad en mentorskap en Karen Welman se vriendskap en geselsies oor ‘n koppie koffie in die vroeë oggende en laat aande van navorsing en atlete toets.
Reaserch study: The functional fitness capacity of adults with Down syndrome in South Africa
Purpose: The purpose of the study was to establish the functional fitness capacity of Down syndrome (DS) adults. The study also analysed which physical attributes predict functional fitness performance.
Methods: Data were collected at various intellectual disability centres and private homes in 7 provinces of South Africa. 371 DS individuals (199 men and 172 women) from 18-66 years were tested for balance, flexibility, coordination, muscular strength and endurance, aerobic capacity and functional ability. Data were categorised according to gender and age groups (18-25, 26-35, 36-45, and > 45 years). Multiple regression analysis was performed to determine the relationship between the functional task and physical test items.
Results: DS men performed significantly better on all but two tests compared to the women (P<0.05). DS women performed better on the sit-and-reach flexibility item and the chair stand test however, differences were not statistically significant from the men. Significant differences across age groups were observed for 9 of the 13 functional fitness tests (p<0.05). Muscular strength items, especially leg strength, significantly predicted functional performance in DS men and women. Aerobic capacity only predicted functional performance in DS men and sit-and-reach flexibility and dynamic balance only in DS women.
Conclusions: Findings of this study provide important information on the functional capacity of DS adults and show which physical attributes contribute to functional performance. Consequently appropriate training programs can be tailored for this population whom is known to have poor functional fitness.
Current position: Lecturer at NWU (Mafikeng Campus)
Gunsteling lab herinnering: My gunsteling herinnering van die lab was al die oefenfisiologie toetse wat ons gedoen het partykeer op elite en subelite atlete en al die “parties wat ons labrats met prof T en Karen gehad het”. We worked hard and partied hard! Asook om die enigste man in die lab te wees saam ‘n klomp vrouens was vet-pret.
Reaserch study: The effects of backward locomotion as part of a rehabilitation program on the functional ability of patients following knee injury
Summary: Knee injuries are common among the physically active population and are often severe enough that it requires surgery. Rehabilitation specialists are on the constant look-out for the most efficient and cost-effective treatment alternatives to provide athletes with an early return to sport. The inclusion of backward locomotion in knee rehabilitation programs has been proposed since it is considered a safe closed kinetic chain exercise which has been found to increase quadriceps strength and power as well as cardiorespiratory fitness.
The primary aim of the study was to establish the efficacy of backward locomotion training during a knee rehabilitation program.
Thirty nine men and women (aged 18 to 59 years) with knee pathologies volunteered for the study and were randomly assigned to the experimental group (EXP, n = 20) and control group (CON, n = 19). All participants underwent a 24 session knee rehabilitation program which included 20 – 30 minutes of cardiorespiratory training, either in backward mode (EXP), or forward mode (CON). Aerobic fitness, quadriceps and hamstrings strength and power, single leg balance, lower limb circumferences, and lower limb flexibility were measured before and after the rehabilitation program.
Backward locomotion training resulted in a borderline statistical significant improvement in ventilatory threshold (VT) (p = 0.07) and a statistical significant improvement in peak power output (PPO) (p < 0.05). The VT and PPO of the backward locomotion group increased by 9 and 14%, respectively, compared to 0 and 4% in the forward locomotion group. Both groups showed statistically significant improvements in quadriceps and hamstrings strength, except the quadriceps of the uninvolved leg of the forward locomotion group. Similarly, both groups showed a statistically significant improvement in quadriceps and hamstrings average power, except the quadriceps of the uninvolved leg of the forward locomotion group. Single leg balance of the involved and uninvolved legs improved statistically significantly in both groups (p < 0.05). The differences in change between the two interventions were not statistically significantly different (p > 0.05) and the practical differences were small (ES ± 0.2). No statistically significant differences in the change in leg circumferences were observed between the two groups. Only the change in flexibility of the involved soleus was significantly different between the EXP and CON groups.
The results show that backward locomotion training result in greater improvements in aerobic fitness and equal or greater improvements in quadriceps and hamstrings muscle strength and power, compared to forward locomotion training. Backward locomotion as well as forward locomotion contributes to the recovery of knee injuries, however, the practical significance of backward locomotion is greater than for forward locomotion. The conclusion of this is that backward locomotion is a better alternative rehabilitation program for athletes as this will affect a quicker return to their sport.
Currently working in Switzerland as a contract coordinator at Celgene, a biopharmaceutical company specializing in the discovery, development, and commercialization of therapies designed to treat cancer and immunological disorders.
Gunsteling herinnering van die lab:
Ek het in 2010 in the lab gewerk. Daardie jaar is die Sokker Wereldbeker gehou in SA. Terwyl Prof. T op een van haar oorsese konferensie was, het ons die kleurprinter gebruik om al die landsvlae (van die lande wat deelgeneem het aan die Wereldbeker), op A4 bladsye in kleur te print. Ons het dit aan tou vasgemaak en in die lab gehang. Toe Prof. T terugkom van haar uitstappie af, het sy die ding net 1 kyk gegee en maar nie vrae gevra nie.
Research study: Body composition and functional fitness capacity of young academy soccer players in South Africa and Zimbabwe
Talent identification and early selection into a professional soccer academy has been reported to be very important for the long term development of footballing expertise (Le Gall et al., 2010). This awareness of the need for early identification of gifted youngsters has led to an increased number of soccer centres of excellence and academies throughout the world. Traditionally, identification and selection of promising individuals into youth soccer academies has been linked to a coach’s subjectivity and preconceived image of the player. Once this method is used in isolation it can result in tedious misjudgements in talent identification – hence the emphasis on science-based approaches. Through soccer-specific research, a number of anthropometric and physical parameters have been linked to successful performance in soccer. The primary aims of the study were to explore the anthropometric, somatotype and functional fitness characteristics of young academy soccer in South Africa and Zimbabwe and to distinguish variables that can be relevant for Talent Identification. The study followed a quantitative non-intervention design with a sample of convenience. A total of 74 young soccer players (Age 15.9±0.81) from South African (n = 41) and Zimbabwean (n = 33) soccer academies were purposively sampled. The following anthropometric variables were measured following the International Society of the Advancement of Kinanthropometry (ISAK) protocol: body mass and height; skinfolds – (triceps, subscapular, biceps, iliac crest, supraspinale, abdominal, front thigh, medial calf); Girths – (arm relaxed, arm flexed and tensed, waist, gluteal, and calf); bone breadths – (biepicondylar humerus and biepicondylar femur). Functional fitness variables that were measured include: lower back muscle flexibility (sit and reach test), upper body flexibility (shoulder flexibility), leg power using (vertical and horizontal jumps), overhead throw (2kg medicine ball throw), speed tests (10, 20, and 40m sprint tests), agility (Illinois test) and aerobic fitness (Hoff test). There were no statistically significant differences in age, body mass, height, fat mass, body mass index, lower back flexibility, right shoulder flexibility, 20m sprint, and endurance capacity (p>0.05). Statistically significant differences were found in percentage body fat (p>0.05), sum of 8 skinfolds, fat free mass, somatotype, left shoulder flexibility, upper and lower body power, 10m and 40m sprints (p<0.01). South African players were found to have higher %BF and sum of skinfolds and then Zimbabwean players. It was concluded that Zimbabwean players performed significantly better than South Africans in agility, 10m, 40m sprints, vertical jump, horizontal jump and overhead throw and had better future chances of success in soccer. Goalkeepers were taller and heavier, while midfielders and defenders were found to be lighter and shorter. Goalkeepers were the most agile group, while forwards were the fastest group. Agility, power and speed were the most important variables that can be used during talent selection and coaches should purposefully work to develop these characteristic during training sessions. Height and weight are relevant in allocating positional roles to players and not in Talent Identification.
Current position: Lecturer at Zimbabwe Open University.
Areas of teaching: Anatomy and physiology; Exercise physiology; Testing and measurement and soccer.
Summary about PhD
The purpose of this thesis was to determine the effects of three different exercise training modalities (resistance training, high-intensity interval training and moderate continuous training) on physical and cognitive function, as well as cerebral oxygenation in healthy older adults.
The findings of this thesis demonstrated that the enhancement of physical and cognitive function is dependent on the exercise training mode. HIIT was superior for gains in submaximal endurance capacity, whereas only RT showed a statistically significant improvement in executive cognitive function, with HIIT exhibiting a similar trend. In addition, both resistance and aerobic training are beneficial for cerebral oxygenation during cortical activation, compared to no exercise. It was found that the latter is training mode dependent, with aerobic exercise proving more effective.
Summary about PhD
The incidence of Type 2 diabetes is rapidly increasing globally, and in South Africa, with men and women of all ages being affected. The International Diabetes Federation estimates that in 2015 approximately 2 million South Africans had diabetes and 57,318 died because of complications related to the disease. With these numbers set to rise, efforts to curb diabetes are urgently needed.
As part of my PhD project we sought to implement a 10-week holistic lifestyle intervention program in a low socio-economic status community, in an effort to help people suffering with type 2 diabetes adequately manage their disease. The program was a great success with improvements seen in blood glucose management, cardiovascular ability, body fat and blood pressure. Furthermore, dietary behaviours and health related quality of life improved dramatically.
The long-term plan is to refine the program and extend it into other deserving communities in and around Stellenbosch, and nationally.
Current position: I am currently involved in my own private Biokinetics practice in Stellenbosch.
Favourite memory of working in the lab: Always being well represented on the odd comments white-board.
This study aimed at determining the influence of running specific prostheses on the performance of an athlete with a unilateral lower limb amputation. We firstly defined some of the mechanical characteristics of the different prostheses models. We then tested the different models of prostheses on an athlete with a unilateral transtibial amputation. This was aimed at determining what influence the different mechanical characteristics as determined in the initial testing has on the physiological and biomechanical performance of the athlete. From these tests we determined that increased stiffness of the prosthesis is more efficient for longer distance sprints such as the 400m. This may be due to a decrease in the contact time with the stiffer prostheses, which decreases the physiological strain on the athlete.