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A method for tuning the spring rate and damping rate of a mountain bike suspension based on a data-driven procedure is presented. The design and development of a custom data acquisition system, known as the "MTB DAQ," capable of measuring acceleration data at the front and rear axles of a bike are discussed. These data are input into a model that is used to calculate the vertical acceleration and pitching angular acceleration response of the bike and rider. All geometric and dynamic properties of the bike and rider system are measured and built into the model. The model is tested and validated using image processing techniques. A genetic algorithm is implemented with the model and used to calculate the best spring rate and damping rate of the mountain bike suspension such that the vertical and pitching accelerations of the bike and rider are minimized for a given trail. Testing is done on a variety of different courses and the performance of the bike when tuned to the results of the genetic algorithm is discussed. While more fine tuning of the model is possible, the results show that the genetic algorithm and model accurately predict the best suspension settings for each course necessary to minimize the vertical and pitching accelerations of the bike and rider.

This investigation examined the acute physiological demand associated with a typical Freeride Mountain Bike (FMB) ride. Measures of cardiovascular strain (heart rate, RPE) and neuromuscular fatigue (quarter squat and handgrip MVICs) were assessed in 22 experienced mountain bikers during an observed ride on Mt. Fromme in North Vancouver, British Columbia. The ride involved an initial ascent of 350 vertical meters over horizontal distance of 5.93km, (mean duration 46.61 min). The descent covered a 350m loss in elevation through intermediate to expert level trails spanning a horizontal distance of 4.24km, (mean duration 28.55 min). Heart rate monitoring was continuous. Blood Lactate was assessed pre-ride, at the top of the ascent (mid-ride), and following the descent (post-ride). RPE was assessed mid-ride and post-ride. Handgrip and quarter squat MVICs were taken pre-ride and post-ride. An a priori alpha of .05 was set for all statistical tests. Both measures of neuromuscular strain decreased pre-post ride, equal to 2.8% in quarter squat MVIC and 6.1% and 4.3% in handgrip MVIC for the right and left hands respectively. Blood lactate increased from rest to mid-ride and decreased from mid-ride to post-ride. The mean heart rates (- 80% PHRmax) and RPEs (-14.5) associated with the ascent and descent were not significantly different. The acute physiological and ride pattern data indicate that FMB satisfies the American College of Sports Medicine's guidelines for increasing cardiovascular health and fitness.

This investigation examined the acute physiological demand associated with a typical Freeride Mountain Bike (FMB) ride. Measures of cardiovascular strain (heart rate, RPE) and neuromuscular fatigue (quarter squat and handgrip MVICs) were assessed in 22 experienced mountain bikers during an observed ride on Mt. Fromme in North Vancouver, British Columbia. The ride involved an initial ascent of 350 vertical meters over horizontal distance of 5.93km, (mean duration 46.61 min). The descent covered a 350m loss in elevation through intermediate to expert level trails spanning a horizontal distance of 4.24km, (mean duration 28.55 min). Heart rate monitoring was continuous. Blood Lactate was assessed pre-ride, at the top of the ascent (mid-ride), and following the descent (post-ride). RPE was assessed mid-ride and post-ride. Handgrip and quarter squat MVICs were taken pre-ride and post-ride. An a priori alpha of .05 was set for all statistical tests. Both measures of neuromuscular strain decreased pre-post ride, equal to 2.8% in quarter squat MVIC and 6.1% and 4.3% in handgrip MVIC for the right and left hands respectively. Blood lactate increased from rest to mid-ride and decreased from mid-ride to post-ride. The mean heart rates (- 80% PHRmax) and RPEs (-14.5) associated with the ascent and descent were not significantly different. The acute physiological and ride pattern data indicate that FMB satisfies the American College of Sports Medicine's guidelines for increasing cardiovascular health and fitness.

Ce travail de thèse s'articule autour des caractéristiques de la performance dans la discipline du Vélo Tout-Terrain Cross-Country Olympique (VTT XCO). La performance produite dans une situation d’interaction homme-matériel résulte de l’adéquation optimale entre le pratiquant et son matériel. Elle résulte aussi bien de facteurs mécaniques (géométrie et rigidité du cadre, réglage des suspensions, taille des pneumatiques, transmission), biomécaniques (adoption d’un patron de pédalage adapté au terrain), physiologiques (économie du geste, endurance, fatigue) ou encore motivationnels (confiance en soi). La discipline spécifique du XCO a fortement évolué, au niveau réglementaire et technologique, depuis un peu moins d'une décennie. C’est pourquoi l’objectif de mes recherches a été de caractériser à la fois la performance in-situ et en laboratoire de manière à améliorer notre compréhension de la discipline dans son état actuel, afin de proposer des interventions au niveau de l'entrainement et sur des aspects plus fondamentaux du geste de pédalage en VTT. En s’intéressant notamment à la pratique de haut-niveau, à la dynamique des efforts et à certains aspects biomécaniques du pédalage, les résultats de ces travaux nous ont permis de mettre en évidence que le format actuel de course correspond à une épreuve de haute intensité à la fois acyclique et intermittente, mais aussi que la modification du matériel n’entraine pas forcément de changement dans le pattern de pédalage des coureurs. / This thesis focuses on performance characteristics in the Cross-Country Olympic Mountain Bike (MTB XCO) discipline. The performance produced in a man-material interaction situation results from the optimal adequacy between the rider and his equipment. It results as much from mechanical factors (frame geometry and rigidity, suspension adjustment, tyre size, transmission) as biomechanical (adoption of a pedalling pattern adapted to the terrain), physiological (economy of movement, endurance, fatigue) or motivational (self-confidence). The XCO's specific discipline has evolved considerably, both in terms of regulations and technology, in just under a decade. Therefore, the objective of my research has been to characterize both in-situ and laboratory performance in order to improve our understanding of the discipline in its current state, in order to propose interventions at the level of training and on more fundamental aspects of pedalling in mountain bikes. By focusing in particular on high-level practice, the dynamics of effort and certain biomechanical aspects of pedalling, the results of this work have enabled us to highlight that the current racing format corresponds to a high intensity event that is both acyclic and intermittent, but also that changing the equipment does not necessarily lead to a change in the pedalling pattern of riders.

This report presents the conceptual development of an off-road cargo trailer designed for usage in conjunction with bicycles when camping. The objective of the study is to address the limitations of existing cargo trailers and thereafter create a trailer that efficiently can navigate off-road terrains while carrying various types of cargo. The research includes collecting data regarding user behaviours and desired functions an optimal trailer should obtain and was translated into user requirements. The result demonstrates the successful development of an off-road cargo trailer on a conceptual level that offers innovative solutions and improved load-carrying capacity in comparison to the available market, while considering factors such as weight, manoeuvrability, and ease of use. This research contributes to the field by presenting data, which can be used in development and a comprehensive solution that expands the possibilities for bicycle-based cargo transportation in off-road environments. Future work can include further refinements to optimise the trailer’s performance and address additional user requirements based on the data presented.

Thesis (MScSportSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The purpose of this qualitative-quantitative study was to describe the exercise intensity and predictors of performance of a multi-stage mountain bike (MTB) race (2014 Absa Cape Epic) lasting 8 days. Twenty-three amateur mountain bikers (age 39 ± 9 years, height 178.8 ± 8.2 cm, body mass 74.7 ± 9.1 kg, VO2max 54 ± 7 ml.kg-1.min-1) who completed the 2014 Absa Cape Epic were involved in the study. The participants were divided into two groups according to their MTB experience. The experienced group included participants who previously completed more than three 3-day multi-stage MTB events and the novices group included those who has completed less than 3-day multi-stage MTB events. Prior to the event the participants completed a maximal aerobic cycling test and a simulated 40 km time trial (TT). The maximal aerobic test was used to determine 3 work intensity zones based on heart rate (HR) corresponding to blood lactate thresholds (LT: increase in blood lactate concentration of 1 mmol.l-1 above baseline values and the onset of blood lactate accumulation (OBLA), a fixed blood lactate concentration of 4 mmol.l-1). There were no statistically significant differences in the physical, physiological and performance variables measured in the laboratory between the two groups. The exercise intensity during the Cape Epic was measured using telemetric HR monitoring sets. RPE values were noted after each stage of the race. The mean HR was 88.1 ± 5.3% (experienced) and 84.2 ± 11.0% (novices) of maximal HR during the race or 88.9 ± 3.5% (experienced) and 85.9 ± 10.6 (novices) of laboratory determined maximum HR. More time was spent in the “low” HR zone (43.1 % vs 58.5 %, respectively), while only a small amount of time was spent in the “hard” HR zone (7.4% and 6.1%, respectively). The experienced group spent statistically significantly more time in the “moderate” HR zone compared to the novices group (49.5 % vs. 35.4 %). The experienced group performed significantly better during the event compared to the novices group in both the total event time (P = 0.004) and the general classification (P = 0.01). Relative and absolute power output (PO) at OBLA (P = 0.01 and 0.02, respectively) were statistically significant predictors of total event time, while relative peak power output was a significant predictor of general classification for the event (P = 0.02) . The total TT time was a significant predictor of average event HR (P = 0.03). This study showed that this MTB stage race is physiologically very demanding and requires cyclists to have excellent endurance capacity, as well as strength and power. The parameters from the maximal aerobic capacity test correlated better with outdoor performance than parameters from the simulated 40 km TT. Therefore the standard maximal aerobic capacity test are sufficient for testing mountain bikers and sport scientists can continue using this test to prescribe exercise intensity zones for training and events. / AFRIKAANSE OPSOMMING: Die doel van hierdie kwalitatiewe-kwantitatiewe studie was om die oefeningsintensiteit en voorspellers van prestasie tydens ‘n multi-dag bergfiets kompetisie (Absa Cape Epic) van 8 dae lank te bepaal. Drie-en-twintig bergfietsryers (ouderdom 39 ± 9 jaar, lengte 178.8 ± 8.2 cm, liggaamsmassa 74.7 ± 9.1 kg, VO2maks 54 ± 7 ml.kg-1.min-1) wat die 2014 Absa Cape Epic voltooi het, het aan die studie deelgeneem. Die deelnemers is in twee groepe verdeel volgens hulle ervaring in multi-dag bergfiets kompetisies. Die ervare groep was al die deelnemers wat meer as drie 3-dae multi-dag bergfiets kompetisies voltooi het. Die onervare groep was al die deelnemers wat minder as drie 3-dag multi-dag bergfiets kompetisies voltooi het. Voor die kompetisie het al die deelnemers ‘n maksimale aërobiese toets en ‘n gesimuleerde 40 km tydtoets in die laboratorium voltooi. Die maksimale aërobiese toets is gebruik om drie werk intensiteit sones volgens die hartspoed te bepaal, naamlik die hartspoed by die laktaatdraaipunt(‘n toename in bloed [laktaat] van 1 mmol.l-1 bo die basislynwaardes) en die hartspoed by die aanvang van bloedlaktaat akkummulasie (‘n vaste bloed [laktaat] waarde van 4 mmol.l-1). Daar was geen statisties betekenisvolle verskille in die fisiese, fisiologiese en prestasie veranderlikes tussen die twee groepe nie. Die oefeningsintensiteit tydens die Cape Epic was gemeet deur gebruik te maak van hartspoedmonitors. Die RPE waardes was aan die einde van elke skof genoteer. Die gemiddelde hartspoed was 88.1 ± 5.3 % (ervare) en 84.2 ± 11.0 % (onervare) van maksimale kompetisie hartspoed, of 88.9 ± 3.5 % (ervare) en 85.9 ± 10.6 % (onervare) van die maksimale hartspoed soos in die laboratorium gemeet. Die fietsryers het meer tyd spandeer in die “lae” hartspoed sone (43.1 % vs 58.5 %, onderskeidelik), in vergelyking met die “moeilike” hartspoed sone (7.4 % vs 6.1 %, onderskeidelik). Die ervare groep het statisties betekenisvol meer tyd in die “matige” hartspoed sone spandeer (49.5 % vs. 35.4 %) in vergelyking met die onervere groep. Die ervare groep het beter presteer tydens die kompetisie vir beide totale kompetisie tyd (P = 0.004) en algehele klassifikasie (P = 0.01). Relatiewe en absolute krag by aanvang van bloed laktaat akkumulasie was statisties betekenisvolle voorspellers van totale kompetisie tyd (P = 0.01 en 0.02, onderskeidelik), terwyl maksimale krag ‘n statisties betekenisvolle voorspeller was van algehele klassifikasie in die kompetisie (P = 0.02). Die totale tydtoets tyd was ‘n statisties betekenisvolle voorspeller van gemiddelde hartspoed tydens die kompetisie. Die studie het gewys dat hierdie multi-dag bergfiets kompetisie fisiologies baie uitdagend is en dat fietsryers uistekende uithouvermoë kapasiteit, sowel as krag en plofkrag moet besit. Die veranderlikes van die maksimale aërobiese toets het beter met prestasie in die veld gekorreleer as die veranderlikes van die gesimuleerde 40 km tydtoets. Daar word dus afgelei dat die standaard maksimale aërobiese toets voldoende is vir die toetsing van bergfietsryers en sportwetenskaplikes kan aanhou om hierdie toets te gebruik om oefeningsintensiteit sones voor te skryf vir oefensessies en kompetisies.

Conflict in recreation is a major problem for recreation managers who are trying to provide satisfying experiences for all recreationists. This thesis is about conflict between mountain-bikers and trampers. Mountain-biking has grown in popularity in New Zealand over the last ten years, and these increasing numbers have threatened the quality of walkers' and runners' recreational experiences, particularly in peri-urban areas. Conflict is a complex social interaction process which occurs around times of change. It involves the interplay of perceptions and attitudes, behaviour, and an incompatible situation. This complexity required the use of a range of methods to successfully understand the conflict between walkers and mountain-bikers. Like many other recreational conflicts, the conflict between bikers and trampers is asymmetrical - walkers dislike meeting bikers much more than bikers dislike meeting walkers. A majority of walker respondents disliked or strongly disliked meeting bikers on walking tracks. Walkers' questionnaire answers indicated that their greatest concerns with mountain-biking are (in order of decreasing importance) track damage and other environmental damage, personal safety, and the feeling that bikes interrupt their peace and quiet. Further exploration during in-depth interviews show that the perception of these problems are closely related to the way different users feel about that places that they use, and the way meetings with other users can be incorporated into the experiences of the recreationist. For walkers, meeting bikers is far more intrusive than vice-versa. Political activity aimed at eliminating bikers from many front country areas means that bikers are now developing a dislike of trampers who they see as intolerant and arrogant. Therefore, behaviour affects the escalation of conflict. In addition, wider social change has had an influence on this conflict. Changing economic wellbeing, less regular work hours, a perceived lack of time and a wider choice of activities have all impacted on recreation patterns in peri-urban areas, and on this conflict situation. In addition, this study has indicated that the concepts of specialisation and substitution may need modification. The use of qualitative methods has highlighted the narrow focus that researchers have used when studying these concepts. Both must be seen more broadly in the context of individuals' changing recreational needs both over the life cycle, and in the face of social change as outlined above.